chemistry education research and practice effect of peer-led team...a total of 1849 students from...

694 | Chem. Educ. Res. Pract., 2018, 19, 694--710 This journal is©The Royal Society of Chemistry 2018

Cite this: Chem. Educ. Res. Pract.,

2018, 19, 694

The effect of peer-led team learning onundergraduate engineering students’ conceptualunderstanding, state anxiety, and social anxiety†

E. N. Eren-Sisman, *a C. Cigdemoglu b and O. Geban a

This study aims to compare the effectiveness of a Peer-Led Team Learning (PLTL) model with that of

traditional college instruction (TCI) in enhancing the conceptual understanding and reducing both the

state anxiety and social anxiety of undergraduate engineering students in a general chemistry course in a

quasi-experimental design. 128 engineering students taking the course participated in the study. One of

the course sections was randomly assigned to the experimental group and the other section was assigned

to the control group. Both sections were taught by the same instructor. The control group was instructed

using traditional college instruction, while the experimental group was instructed using the PLTL model.

Throughout this study, six peer-led chemistry workshops and leader training sessions were performed

simultaneously. The General Chemistry Concept Test, the State–Trait Anxiety Inventory, and the Social

Anxiety Questionnaire for Adults were administered before and after the treatment to both groups. One-

way Multivariate Analysis of Covariance (MANCOVA) indicated that after controlling students’ university

entrance scores, trait anxiety scores and pre-test scores of both the General Chemistry Concept Test and

state anxiety, the PLTL model was more effective in improving the conceptual understanding and reducing

the situational anxiety of engineering students in undergraduate general chemistry. However, it was not so

effective in lessening their social anxiety when compared to traditional college instruction.

Introduction

Despite rapid advances in technology, the number of studentschoosing science, technology, engineering, and mathematics(STEM) and related careers has decreased progressively withtime, while the rates of students’ retention in these fields haveremained steady or decreased (Higher Education ResearchInstitute, 2010). A high rate of attrition or dropouts of studentsin post-secondary and tertiary education is another significantproblem, and the reasons are attributed to having low levels ofstudents’ success and effort in their learning (e.g., Lovitts,2001), having differences in the learning approach (e.g., Tobias,1990), having problems related to pedagogy, student assessment,curriculum design and guidance (e.g., Seymour and Hewitt, 1997),and having problems in basic competencies – creative problem-solving skills, study skills, complex communication skills, self-development and critical thinking skills (e.g., Gafney andVarma-Nelson, 2008). Various methods such as summer programs,

active-learning techniques, and structured research experiencesfor undergraduates have been recommended by institutions toremedy those problems (Drane et al., 2014). According to Tinto(1975), one way of doing this is by improving the instruction ina way that students feel a sense of belonging to an academicsociety. Tobias (1992) also stresses the crucial role of mentoringin students’ careers. Besides, ‘‘the most powerful source ofinfluence on growth and development during the undergraduateyears’’ was reported as the employment of students’ peer groups(Astin, 1993, p. 398), which is not included in traditionalinstruction.

Peer-led team learning (PLTL)

Peer-Led Team Learning (PLTL) is one of the instructionalmodels which have been implemented by numerous facultiesand institutions in STEM courses to overcome such problems.It creates an active learning environment where students con-struct their own knowledge, communicate more effectively withone another, review the lecture material, have opportunity toask questions and think more deeply about the conceptual sideof their learning using higher-level reasoning and problemsolving skills (Tien et al., 2002; Varma-Nelson and Coppola,2005; Varma-Nelson, 2006). It was first introduced in generalchemistry as ‘‘Workshop Chemistry’’ supported by the National

a Department of Mathematics and Science Education, Faculty of Education, Middle

East Technical University, 06800, Ankara, Turkey. E-mail: [email protected],

[email protected] Department of Educational Sciences, Atılım University, 06830, Ankara, Turkey

† This study is part of the first author’s doctoral dissertation.

Received 20th October 2017,Accepted 28th March 2018

DOI: 10.1039/c7rp00201g

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Science Foundation (NSF) for systemic change in chemistry inthe early 1990s and this was followed by many institutions acrossSTEM disciplines (Gafney and Varma-Nelson, 2008). In PLTL,lectures are first presented by course instructors and then theselectures are supplemented with PLTL workshops in which asuccessful undergraduate student guides a team of students inweekly meetings to solve problems developed by the courseinstructor. In a typical workshop session, a group of 6–8 studentsmeet with their peer leader for one or two hours per week todiscuss the topics and solve the problems related to the coursecontent by providing conceptual understanding and criticalthinking (Gafney and Varma-Nelson, 2008). A PLTL workshopis different from a conventional recitation session since its coreactivity is discussion and debate on the concepts and ideas thatform the basis for solving the problems. Unlike a teacher inthe traditional classroom or a teaching assistant in demon-strating how to solve the problem, a peer leader is a facilitatoror guide who earned at least a B grade in the same course inthe previous years. The role of the peer leader is to engagethe group in problem-solving activities, assist students indeveloping conceptual understanding, support students toreach their full potential and facilitate discussion of scientificconcepts and ideas (Roth et al., 2001a, 2001b; Gafney andVarma-Nelson, 2008).

As a second-generation pedagogy, PLTL is the combination ofwell-established theories and methods for instructional designsuch as group learning, reciprocal teaching, studio instruction,and social constructivism (Varma-Nelson et al., 2004; Varma-Nelsonand Coppola, 2005). Group learning, reciprocal teaching, andstudio instruction have their theoretical base in social con-structivism in which students build their knowledge from aninteraction between the previously learned concept and newknowledge and skills by discussing and criticizing the ideas in asocial and collaborative environment (Phillips, 2000; Gredler,2009). Vygotsky, as a social constructivist, advocates that com-munity plays a fundamental role in the process of makingmeaning and development of cognition because cognitive skillsand thinking patterns are determined in the social and culturalcontexts of the learning environment (1978). Two significantideas in the work of Vygotsky consist of the roots of PLTL. First,the interaction with a more knowledgeable and skilled peer orteacher is an effective way of developing skills and strategies. Inother words, knowledge is scaffolded with the support of amore experienced and successful learner. Second, tasks andactivities should be designed for students in order to enhancetheir level of performance. Vygotsky proposed the conceptof the Zone of Proximal Development (ZPD), which is thedifference between students’ independent problem-solving cap-abilities (lower end of the ZPD) and their potential development(higher end of the ZPD) with the guidance of more knowledge-able peers. When training peer-leaders, as well as designingand selecting appropriate instructional materials, these ideasare key concepts because students cannot solve challengingproblems easily on their own, but they can accomplish bythe interaction with the members of the team and peer leaderswithin their ZPD in chemistry workshops (Cracolice, 2000;

Varma-Nelson and Coppola, 2005; Gafney and Varma-Nelson,2007).

Many studies about the original PLTL model and its severalvariants have been conducted in many different STEM areas.Wilson and Varma-Nelson (2016) summarized research studiesin terms of five types of PLTL variants: (1) peer-led guidedinquiry (PLGI); (2) online PLTL; (3) PLTL in the chemistrylaboratory; (4) utilization of in-class peer leaders; and (5)increased student-to-peer-leader ratios. Since the interventionof this study was performed in a general chemistry course withstandard PLTL, previous studies were examined and analyzedin this regard; see Table 1, which briefly summarizes researchstudies in General Chemistry courses. As can be seen from thetable, PLTL has been generally designed by either comparisonsacross semesters or comparisons in concurrent sections of acourse to improve students’ achievement, course pass rate,retention, self-confidence, engagement, and attitude towardsboth the subject and the course in the First-Semester GeneralChemistry course (Gosser and Roth, 1998; Stewart et al., 2007;Hockings et al., 2008; Lyon and Lagowski, 2008; Kampmeierand Varma-Nelson, 2009; Lewis, 2011; Shields et al., 2012;Drane et al., 2014; Chan and Bauer, 2015) and in the Second-Semester General Chemistry course (Alger and Bahi, 2004;Baez-Galib et al., 2005; Mitchell et al., 2012).

Conceptual understanding

Holme et al. (2015) defined the conceptual understanding ingeneral chemistry as ‘‘applying core chemistry ideas (theories,patterns, relationships, etc.) to chemical situations; reasoningabout these core chemistry ideas using higher order skills;expanding situational knowledge to predict and/or explainbehaviour of chemical systems, demonstrating the criticalthing and reasoning in solving problem; translating acrossscales and representations (p. 1480)’’. Numerous studies haverevealed that since course instructors generally have not sustainedan environment for students to develop conceptual understandingof scientific concepts, students have some alternative conceptionsof these concepts that are in conflict with the consensus of thescientific community (Treagust, 1986; Driver et al., 1994; Duit andTreagust, 2003; Pabuccu and Geban, 2006; Duit et al., 2008).Through team learning, students are able to discuss and negotiatescientific principles, ideas and meaning with peers via criticalthinking, and problem-solving skills to construct their knowledgeand understanding of science concepts in a social context(Varma-Nelson and Coppola, 2005). Therefore, in line withBramaje and Espinosa (2013) too, PLTL is expected to enhancestudents’ conceptual understanding more than traditional ways.

State and social anxiety

In addition to the above-mentioned contributions of PLTL, itpromises to affect students’ state anxiety and social anxiety.State anxiety refers to the temporary emotional state or feelingscaused by a particularly stressful situation at a particularperiod of time or at a particular moment in time, while traitanxiety refers to the permanent and general feeling of anxietyrelated to the personality characteristic (Spielberger et al., 1983).

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Tab

le1

PLT

Lst

ud

ies

imp

lem

en

ted

ing

en

era

lch

em

istr

yco

urs

es

Au

thor

/ye

arPa

rtic

ipan

ts/i

nst

itu

tion

Du

rati

onC

ours

eIn

terv

enti

onG

rou

p/pe

riod

Dep

end

ent

vari

able

sM

ajor

fin

din

gs

Alg

eran

dB

ahi

(200

4)

Stu

den

tsat

Sou

ther

nU

tah

Un

iver

sity

Fall

and

spri

ng

sem

este

rsof

2001

–200

2an

d20

02–2

003

acad

emic

year

s

Firs

t-an

dSe

con

d-

Sem

este

rG

ener

alC

hem

istr

y

Du

rin

g20

02–2

003

|6

to8

stu

den

tspe

rgr

oup

|M

idte

rmex

ams

|PL

TL

grou

ph

adh

igh

erm

ean

san

dm

edia

ns

ofsc

ores

onm

id-t

erm

exam

inat

ion

sth

anT

I

|PL

TL

vs.R

Cw

ith

com

pute

r-ai

ded

inst

ruct

ion

|2

ha

wee

k|

AC

Sfi

nal

exam

s|

Bot

hgr

oups

had

the

sam

em

ean

san

dm

edia

ns

ofsc

ores

onth

eA

CS

fin

alex

ams

du

rin

gth

efa

llse

mes

ter,

wh

ile

the

PLT

Lgr

oup

had

hig

her

scor

esd

uri

ng

the

spri

ng

sem

este

rD

uri

ng

2001

–200

2|

PLT

Lvs

.T

I

Bae

z-G

alib

etal

.(2

005)

Ato

tal

of18

49st

ud

ents

from

chem

istr

y,bi

olog

y,m

ath

e-m

atic

s,ph

ysic

s,an

ded

uca

tion

prog

ram

sat

the

Un

iver

sity

ofPu

erto

Ric

o

Succ

essi

vese

ven

sem

este

rsfr

om19

97to

2000

Firs

t-an

dSe

con

d-

Sem

este

rG

ener

alC

hem

istr

y

|PL

TL:

Ch

em-2

-C

hem

Prog

ram

(C2C

)

|3

ha

wee

k|

Succ

essf

ul

and

un

succ

ess-

ful

cou

rse

outc

omes

|Fo

rbo

thsu

cces

sfu

l(fi

nal

grad

esof

A,

B,

and

C)

and

un

succ

essf

ul

(fin

algr

ades

ofF

and

W)

cou

rse

outc

omes

,th

ere

wer

eh

igh

lyst

atis

tica

lly

sig-

nif

ican

td

iffer

ence

sam

ong

grou

ps,

favo

rin

gth

eC

2Cpr

ogra

m|

TI:

non

-pa

rtic

ipan

ts|

Stu

den

tpe

rcep

tion

ofC

2C

|C

2Cpa

rtic

ipan

tsh

ada

low

wit

hd

raw

alra

te

|C

2Cpa

rtic

ipan

tspe

rcei

ved

the

prog

ram

ina

posi

tive

way

Ch

anan

dB

auer

(201

5)

Am

ajor

ity

ofst

ud

ent

maj

orin

gin

engi

nee

rin

g,sc

ien

ces,

hea

lth

and

hu

man

serv

ices

,an

dli

bera

lar

tsat

the

Un

iver

sity

ofN

ewH

amps

hir

e

Full

y-ra

nd

omiz

edd

esig

nfo

rtw

ofa

lls

of20

08an

d20

09

Firs

t-Se

mes

ter

Gen

eral

Ch

emis

try

Full

y-ra

nd

omiz

ed|

4–9

stu

den

tspe

rgr

oup

|E

xam

ach

ieve

men

tFo

rfu

lly-

ran

dom

ized

stu

dy

Qu

asi-

expe

rim

enta

ld

esig

nin

fall

sof

2004

,20

05,2

006,

2007

,20

11,

2012

,an

d20

13

|PL

TL

Full

yra

nd

omiz

edd

esig

n

|A

ffec

tive

char

acte

rist

ics

(sel

f-co

nce

ptan

dat

titu

de

tow

ard

sch

emis

try)

|T

her

ew

asn

osi

gnif

ican

tdiff

eren

cein

ach

ieve

men

t,at

titu

de,

orse

lf-

con

cept

betw

een

PLT

Lpa

rtic

ipan

tsan

dn

on-P

LTL

part

icip

ants

|N

on-P

LTL

(on

eor

mor

eof

the

foll

owin

gop

tion

s)

|N

earl

yev

ery

wee

k,80

min

in20

08an

d50

min

in20

09

|Fi

rst-

year

stu

den

tsh

adh

igh

erpo

siti

veat

titu

de,

self

-con

cept

,an

dac

hie

vem

ent

than

oth

ers

�Se

lf-o

rgan

ized

stu

dy

grou

ps45

%Q

uas

i-ex

peri

men

tal

des

ign

|M

ale

stu

den

tssh

owed

hig

her

posi

tive

atti

tud

ean

dse

lf-c

once

ptth

anfe

mal

est

ud

ents

�In

stru

ctor

-led

revi

ewse

ssio

ns

|50

min

in20

09an

d20

11w

hil

e80

min

inot

her

year

s

For

quas

i-ex

peri

men

tal

stu

dy

�D

rop-

intu

tori

als

led

bygr

adu

ate

oru

nd

ergr

adu

ate

chem

istr

ym

ajor

s

|PL

TL

part

icip

ants

show

edst

ron

ger

exam

ach

ieve

men

tth

ann

on-P

LTL

part

icip

ants

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Tab

le1

(co

nti

nu

ed)

Au

thor

/ye

arPa

rtic

ipan

ts/i

nst

itu

tion

Du

rati

onC

ours

eIn

terv

enti

onG

rou

p/pe

riod

Dep

end

ent

vari

able

sM

ajor

fin

din

gs

�In

stru

ctor

office

hou

rsQ

uas

i-ex

peri

men

tal

|PL

TL

|T

I

Dra

ne

etal

.(2

014)

All

stu

den

tsen

rolle

din

seve

nco

urs

esfr

omfi

veST

EM

dis

cipl

ines

atN

orth

wes

tern

Un

iver

sity

Ove

ra

10ye

arpe

riod

betw

een

fall

2001

and

spri

ng

2011

Bio

logy

210,

Intr

odu

ctor

yC

hem

101,

Org

anic

Ch

em,

Phys

ics

130,

Phys

ics

135,

Cal

culu

s,an

dE

ngi

nee

rin

g

|PL

TL:

Gat

eway

Scie

nce

Wor

ksh

op(G

SW)

|5

to7

stu

-d

ents

per

grou

p|

Cou

rse

grad

es|

Part

icip

ants

ben

efit

edm

ore

from

GSW

than

TI

inC

hem

istr

yre

gard

less

ofth

eir

gen

der

oret

hn

icit

y

|T

I:n

on-

part

icip

ants

|2

ha

wee

k|

Cou

rse

rete

nti

on|

GSW

part

icip

ants

had

ast

atis

ti-

call

ysi

gnif

ican

th

igh

erre

ten

tion

rate

inC

hem

istr

yth

ann

on-P

LTL

part

ici-

pan

ts,

favo

rin

gm

inor

ity

and

fem

ale

part

icip

ants

Hoc

kin

gset

al.

(200

8)

1125

stu

den

tsfr

omA

rts

and

Scie

nce

s,E

ngi

nee

rin

g,B

usi

nes

s,A

rt,

orA

rch

itec

ture

facu

lty

atW

ash

ingt

onU

niv

ersi

ty

Th

efa

llse

mes

ters

of20

03an

d20

04Fi

rst-

Sem

este

rG

ener

alC

hem

istr

y

|PL

TL

grou

ps|

8st

ud

ents

per

grou

p|

Stu

den

tpe

r-fo

rman

ce(g

rad

e)|

PLT

Lpa

rtic

ipan

tspe

rfor

med

hig

her

and

had

ah

igh

erre

ten

tion

rate

than

non

-PLT

Lpa

rtic

ipan

ts

|N

on-P

LTL

grou

ps|

2h

aw

eek

|PL

TL

stu

-d

ents

’at

titu

de

and

self

-co

nfi

den

ce

|PL

TL

part

icip

ants

had

posi

tive

atti

tud

esto

war

dPL

TL

and

tow

ard

chem

istr

y

|St

ud

ents

expe

ctin

ga

hig

her

grad

ete

nd

edto

view

PLT

Lm

ore

posi

tive

ly|

Fem

ales

felt

mor

eaf

raid

than

mal

esab

out

wor

kin

gin

grou

psan

dfe

mal

esu

sed

mor

evi

sual

sth

anm

ales

tobe

tter

un

der

stan

da

con

cept

Lew

is(2

011)

29ge

ner

alch

emis

try

clas

ses

ina

larg

eu

nd

ergr

adu

ate

inst

itu

tion

loca

ted

inth

eSo

uth

east

ern

Un

ited

Stat

es

NR

Firs

t-Se

mes

ter

Gen

eral

Ch

emis

try

|PL

TL

inst

ruct

ion

|R

eten

tion

|PL

TL

part

icip

ants

had

ast

atis

ti-

call

ysi

gnif

ican

th

igh

erre

ten

tion

rate

than

non

-PLT

Lpa

rtic

ipan

ts

|T

I|

50m

inpe

rw

eek

|A

CS

exam

perf

orm

ance

|B

oth

grou

pssh

owed

equ

ival

ent

perf

orm

ance

onth

eA

CS

fin

alex

am|

12to

16st

ud

ents

per

grou

p;4

stu

den

tspe

rsu

bgro

up

|M

ales

and

fem

ales

had

sim

ilar

gain

sin

pass

ing

the

cou

rse

|M

inor

ity

PLT

Lst

ud

ents

had

the

larg

est

gain

inpa

ssra

tes


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Tab

le1

(co

nti

nu

ed)

Au

thor

/ye

arPa

rtic

ipan

ts/i

nst

itu

tion

Du

rati

onC

ours

eIn

terv

enti

onG

rou

p/pe

riod

Dep

end

ent

vari

able

sM

ajor

fin

din

gs

Lyon

and

Lago

wsk

i(2

008)

348

stu

den

tsat

the

Un

iver

sity

ofT

exas

atA

ust

inSp

rin

gof

2000

Firs

t-Se

mes

ter

Gen

eral

Ch

emis

try

|PL

TL

grou

ps|

4to

5st

ud

ents

per

grou

p

|C

ours

eac

hie

vem

ent

|PL

TL

grou

ph

adsi

gnif

ican

tly

hig

her

perf

orm

ance

than

TI

for

the

fou

rle

ctu

re-o

rien

ted

,h

our-

lon

gex

amin

atio

n|

Non

-PLT

Lgr

oups

|PL

TL

part

icip

ants

rece

ived

hig

her

cou

rse

grad

es

Mit

chel

let

al.

(201

2)

55cl

asse

sof

GC

1an

dG

C2

inan

inst

itu

tion

loca

ted

inth

eSo

uth

east

Un

ited

Stat

es

Fall

and

spri

ng

sem

este

rsof

2009

–201

0an

d20

10–2

011

acad

emic

year

s

Firs

t(G

C1)

and

Seco

nd

-Sem

este

r(G

C2)

Gen

eral

Ch

emis

try

Cas

e1:

GC

1:PL

TL,

GC

2:PL

TL

|50

min

per

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Additionally, social anxiety can be defined as an intense fearof embarrassment or humiliation in social and performancesituations (American Psychiatric Association, 2000). In thescience learning process, some degree of anxiety may be helpfulfor an individual to perform effectively; however, a high level ofanxiety may hinder students’ academic performance by blockingutilization and attention resources, or developing more cognitiveinterference from worries and fears (Mallow and Greenburg,1982).

Moreover, a growing body of research on the role of anxietyemphasizes that anxiety, one of the affective factors, is likely toinfluence students’ achievement and performance in science,and thus, a high level of anxiety can lead to low scienceachievement and academic performance (Czerniak and Chiarelott,1984; Vitasari et al., 2010; Sridevi, 2013). Gafney and Varma-Nelson(2008) conducted focus group studies about the reasons whystudents are so unwilling to ask questions in the classroom. Tworeported causes of students’ failing to ask questions in lecture arefear, anxiety, and stress regarding speaking in a large group andconcern about making comments and asking questions that wouldbe perceived as stupid by the professor and their peers. In contrast,they can easily ask questions in workshops because leaders andpeers are more supportive and accessible. PLTL can alleviate someof the anxiety that students feel in the lecture hall due to publicspeaking and inadequate knowledge. According to Johnson andJohnson (1994), small group work increases students’ criticalthinking abilities, academic achievement, and self-esteem as wellas develops social skills. Since studying in a group environment isable to foster social skills and interaction as well as improveconfidence and self-esteem, it may reduce anxiety about socialsituations.

Significance and purpose of the study

Although there is increasing attention to numerous college-level initiatives and reforms to improve science education andremedy problems in colleges and universities in the USA, suchreforms were not much implemented to foster more activelearning and reduce concerns in higher education of thecountry where the study is conducted. The influence of thismodel on students was not investigated yet for this context. Forthis reason, the study offers a solution to the deficiencies,problems, or obstacles in post-secondary education and servesas an example in this area to implement and disseminate thePLTL model for other universities. As can be seen from Table 1,it is explicit that only a small number of studies have beenconducted to examine the conceptual understanding of students(Alger and Bahi, 2004; Lewis, 2011) and its impact on affectivefactors (Hockings et al., 2008; Chan and Bauer, 2015). Instead,the majority of them aim to investigate its effect on students’pass rate, course performance, and retention. Accordingly,it is worth investigating whether and how PLTL influencesundergraduate engineering students’ conceptual understanding,state anxiety, and social anxiety in general chemistry courses.Based on these purposes, the following research question isinvestigated:

Is there a significant mean difference between the groupsexposed to Peer-Led Team Learning (PLTL) instruction andTraditional College Instruction (TCI) in terms of undergraduateengineering students’ conceptual understanding, state anxiety,and social anxiety in general chemistry courses after controllingsome extraneous variables?

MethodologyResearch design

A quasi-experimental non-equivalent pre-test/post-test controlgroup design was used to compare the effect of peer-led teamlearning with that of traditional instruction on improvingstudents’ conceptual understanding and alleviating students’state and social anxiety. In this design, although the groups beingcompared are randomly assigned as control and experimental, thesubjects are not randomly assigned to these groups; instead alreadyformed groups or intact groups are used (Fraenkel and Wallen,2006).

In the current study, participants were enrolled in twosections of the general chemistry course. Since the coursesections were already formed at the beginning of the semester,students could not be assigned to experimental or controlgroups so course sections were randomly assigned as anexperimental group (EG) and a control group (CG) by a randomprocedure. Section numbers were written on a piece of paperand put into a box and then a number was drawn and assignedto the control group and the other number was assigned to theexperimental group. Students in the experimental group wereengaged in PLTL workshops, but those in the control groupreceived no PLTL workshops; in contrast, they took traditionalinstruction only. Before and after the treatment each group wastested. Table 2 briefly describes the design of the study.

Internal validity can be affected by subject characteristics,mortality, location, instrumentation, testing, history, andmaturation, as well as the attitude of the subjects, regression,and implementation (Fraenkel and Wallen, 2006). Some ofthese threats to internal validity can be controlled with thedesign of the study such as subject characteristics, mortality,testing, history, maturation, and regression because groups’general characteristics and other information about mortalityand history were examined after random assignment of thegroups. For example, there were some missing subjects during

Table 2 Research design of the study

Group Pre-test Treatment Post-test

EG GCCT Peer-led team learning (PLTL) GCCTSTAI STAISAQ SAQ

CG GCCT Traditional college instruction (TCI) GCCTSTAI STAISAQ SAQ

Note. EG: experimental group, CG: control group, GCCT: GeneralChemistry Concept Test, STAI: State–Trait Anxiety Inventory, and SAQ:Social Anxiety Questionnaire for Adults.


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the data collection of pre-tests; however, the number of studentswho were lost was about the same in both groups. Fraenkel andWallen (2006) state that in studies comparing groups if the lossof subjects in all groups is very close to each other, mortality ismost likely not to be a big issue. Besides, there may be a problemresulting from the location but the nature of PLTL is group workand the location of the regular university classroom is notsuitable for that collaborative work. On the other hand, thelocation in which data were collected was the same for bothgroups. In this kind of study, a researcher’s beliefs or expecta-tions can also cause him or her to unconsciously influence theparticipants; however, we observe only the processes and inter-fere with only the organizational arrangements during the work-shop time. After all, leaders played the key role in providingcommunication. In addition, researchers observed some lecturehours and whole workshops. Throughout the implementation ofthe study, both groups had the same professor in lecture hoursso there is no teaching ability difference. As a result, leaders andthe instructor showed no overt bias in favor of PLTL over TCI orvice versa.

Setting and participants

All undergraduate engineering students have taken GeneralChemistry as a must course at the University where the mediumof instruction is English. CEAC 105 General Chemistry is a one-semester course which combines the concepts of first andsecond-semester General Chemistry courses. This course isinstructed in three 50 minute lecture sessions per week andthree 50 minute laboratory sessions biweekly. In the fall seme-ster of the 2016–2017 education year, two intact sections of theCEAC 105 General Chemistry course were selected. The instruc-tor had about 20 years of experience in teaching this course andshe was a volunteer for participating in the study. For theexperimental group, PLTL was a combination of two thirds

teacher-centered lecture interspersed with one third chemistryworkshop including student–peer discussion and problem-solving. Thus, it was a course requirement that all studentsparticipate in the peer-led chemistry workshops. On the otherhand, for the control group, the traditional instruction stylewas a teacher-centered lecture at weekly three 50 minuteperiods. The two comparison groups in this study were deter-mined as illustrated in Fig. 1.

Course enrollments for experimental group and controlgroup sections were 181 and 174, respectively, in that semester.If the students in section 1 completed both the pre-tests andpost-tests or only the post-tests, they were taken as the sampleof the control group. If the students in section 2 completedboth the pre-tests and post-tests or only the post-tests as well asattended at least 50% of the PLTL sessions, they were taken asthe sample of the experimental group. Students who did notcomplete these conditions were dropped out of the analysis. Alldemographic data in terms of students’ age, gender, major, andachievement level based on university entrance scores (LYSscores) were checked with the help of the registrar’s officeand compared between participants of the study and non-participants and between the experimental group and thecontrol group to avoid bias among them. The majority of thestudents were 19 years old for both participants (P) and non-participants (NP) of the study. The gender percentages werealso very close for participants (78% male students and 22%female students) and non-participants (79% male students and21% female students). Both had students from six differentmajor areas (27% of P and 14% of NP in electrical andelectronics engineering, 3% of P and 14% of NP in manufactur-ing engineering, 17% of P and 22% of NP in mechatronicsengineering, 33% of P and 22% of NP in civil engineering, 5%of P and 11% of NP in automotive engineering, and 15% of Pand 17% of NP in software engineering).

Fig. 1 Process by which students were included in the sample. Note:participants who did not complete the pre-tests were retained in the sample aftermissing data analysis was conducted.


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Although some of the percentages for both groups were notclose to each other, the university entrance scores (LYS scores)for each major varied between 220 and 400. The LYS meanscores, which were 295.37 for participants and 287.93 for non-participants of the study, are not different from each other(SDP = 37.37, SDNP = 33.14; t(353) = 1.77, p = 0.084). As a result,it was seen that they were similar in such characteristics.

Moreover, the subjects of the study consisted of 128 under-graduate engineering students with different majors (electricaland electronics engineering, manufacturing engineering, andmechatronics engineering for the control group, and civilengineering, automotive engineering, and software engineeringfor the experimental group). Of them, 28 were females and 100were males. 60 (47 males and 13 females) of the participantswere in CGs and 68 (53 males and 15 females) of them werein EGs. The age range of the students was between 18 and27 years, generally centering on 19 years.

In addition, 14 students were chosen in this study as peerleaders from individuals who had attended the CEAC 105General Chemistry course previously and completed it successfully.Purposive sampling was used to select peer leaders because peerleaders should have some requirements and characteristics for theproper implementation of PLTL chemistry workshops such assuccessful students as well as higher level skills about leadership,communication, and group work. All participants in this studysigned the voluntary participation and acceptance form.

Data collection

In order to assess students’ conceptual understanding andanxiety levels in many different circumstances, three instrumentswere used as pre-tests and post-tests: the General ChemistryConcept Test (GCCT), the State–Trait Anxiety Inventory (STAI),and the Social Anxiety Questionnaire for Adults (SAQ). The detailsof these instruments are explained below.

General Chemistry Concept Test (GCCT). The GCCT wasdeveloped by the authors to assess students’ conceptual under-standing in the general chemistry course. During the develop-mental process of the test, questions in chemistry textbooks,master’s theses, dissertations, journal articles (Mulford andRobinson, 2002; Uzuntiryaki, 2003; Bozkoyun, 2004; Pabuccu,2004; Pabuccu and Geban, 2006; Yalcınkaya, 2010; Kaya, 2011;Al-Balushi et al., 2012; Ayyıldız and Tarhan, 2012; Brown et al.,2013), and high-stakes tests such as ACS Chemistry OlympiadExams (American Chemical Society [ACS], 2016) and AdvancedPlacement (AP) Chemistry Exams (College Board, 2016) wereanalyzed. One question from an ACS Olympiad local sectionexam (ACS, 2014) and four questions from sample multiplechoice questions of AP Chemistry (College Board, 2014) wereused with their copyright notice. Then, items were constructedand examined by three chemistry educators with regard tocontent validity and format. After all revisions, 30 multiplechoice items were identified and some of them were paired. Inthese cases, the first pair represents a chemical or physicaleffect, while the second pair expresses the reason for theobserved effect in the first pair. The incorrect reasons in thesecond pair usually include students’ alternate conceptions or

difficulties related to specific content area gathered from theliterature.

This draft version of the test was piloted with 67 universitystudents who major in chemistry education and engineering beforethe treatment. Item analysis was conducted to check reliability,item difficulty and item discrimination with the SPSS 24.0 program.The mean item difficulty was 0.51, which means a medium level assupported by Crocker and Algina (2008). Furthermore, the meanitem discrimination index was 0.31, which is an acceptable valuebased on the estimated minimum critical value (Crocker andAlgina, 2008). Additionally, items whose biserial correlation indiceswere below the minimum critical value were revised. The Cronbachalpha reliability of the test scores was found to be 0.799, whichindicates high internal consistency (Pallant, 2011).

The final version with 30 multiple choice items was administeredto both groups as a pre-test and post-test. The administration of thetest took approximately 40–45 minutes. The correct answer wasscored as 1 and an incorrect one was scored 0 for each question evenif it was a pair question (Mulford and Robinson, 2002). Thus, astudent can get a maximum of 30 as a total score. The sample itemsare indicated in the Appendix.

State–Trait Anxiety Inventory (STAI). In this study, the last versionof the STAI which was revised by Spielberger et al. (1983) wasimplemented to measure anxiety. The inventory consists of 2subscales: the state anxiety scale and the trait anxiety scale. It hasa total of 40 items with a 4-point Likert-type scale: items 1–20measure situational or state anxiety (STAI-S) and items 21–40measure trait anxiety (STAI-T). Each subscale requires respondentsto rate the degree of various self-statements. In the state anxietysubscale the items were assessed how a respondent feels ‘‘at thismoment’’ or ‘‘right now’’, while in the trait anxiety subscale theitems were assessed how a respondent ‘‘generally’’ feel. Some itemsin the scale are ‘‘I feel secure’’, ‘‘I feel nervous’’, ‘‘I wish I could be ashappy as others seem to be’’, and ‘‘Some unimportant thoughts runthrough my mind and bothers me’’. After reversing scores forpositively-worded items, a total score that a student got from eachscale was a minimum of 20 and a maximum of 80. The high scoreshows a high level of anxiety.

Spielberger (1972) reported test–retest reliability with highschool and college student samples. For the trait anxiety scalethe internal consistency reliability coefficient ranged from 0.65to 0.86, while for the state anxiety scale the internal consistencyreliability coefficients ranged from 0.16 to 0.62. He also speci-fied that, at the time of testing, situational factors may influ-ence the level of state anxiety of respondents so it causes greatchanges in the reliability of the state anxiety scale. In otherwords, it is normal to have a low level of stability in reliability.In the current study, the Cronbach alpha reliabilities for thestate anxiety scale, the trait anxiety scale, and the STAI scalewere found to be 0.915, 0.909 and 0.948, respectively, whichindicate high reliability according to Pallant (2011).

In the present study, the STAI State scale was used to assessthe level of stress that was present at the beginning and todetermine whether students’ anxiety was successfully decreasedafter the intervention. Since it is generally difficult to change traitanxiety, which refers to a permanent personality characteristic,


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the STAI Trait scale was used to specify the level of students’general anxiety at the outset of the term and was adjusted as acovariate in the study.

Social Anxiety Questionnaire for Adults (SAQ). This scale wasdeveloped in different item formats (i.e., 512-item, 118-item,and 82-item versions) by Caballo et al. (2010a). Then, it wasrevised to its 30-item format with a 5-point Likert type scale(known as SAQ-A30) by Caballo et al. (2010b) to measureuniversity students’ uneasiness, stress, or nervousness level insocial situations. SAQ consists of five factors and each has sixitems: speaking in public/talking with people in authority,interactions with the opposite sex, assertive expression ofannoyance, disgust, or displeasure, criticism, and embarrass-ment, as well as interactions with strangers. As examples,‘‘Maintaining a conversation with someone I’ve just met’’ and‘‘Being asked a question in a class by the teacher or by asuperior in a meeting’’ are the social situations in the scale. Astudent can get a maximum of 30 from each dimension and amaximum of 150 from the whole questionnaire. The high scoreon the scale represents that the anxiety level is high.

Caballo et al. (2010b) reported Cronbach’s alpha and thesplit-half reliability coefficient for the whole SAQ to be 0.91, and0.93, respectively. For the current study, Cronbach’s alphareliability was found to be 0.923 and the split-half reliabilitycoefficient was found to be 0.898. The SAQ-A30 scale was usedin the present study to assess undergraduate students’ level ofsocial stress that was present at the outset of the term and todetermine whether such anxiety was successfully decreased atthe end of the term after the intervention.

Treatments

Three months before the implementation, a meeting was held withthe course instructor, the head of the department, and the vicerector of the University and brief information about the model wasgiven. Then, ethical permission from the applied ethics researchcenter was taken. The workshop materials for the PLTL model wereprepared by researchers taking the course curriculum into account.Some revisions were done to these materials by the course profes-sor. Then, the PLTL leaders were selected and began trainingregarding how they could help their team members to solvechallenging team problems in workshops. The experimental groupstudents attended biweekly chemistry workshops. In the weekswhen workshops were not held students attended three lectureperiods. At the end of each workshop, 10 minute quizzes wereimplemented. In order to make the treatment less novel for thecontrol group, the workshop questions were presented to thecontrol group via the learning management system in their course.During the workshop, the course instructor did not attend in ordernot to cause any anxiety in students and leaders and to affectthe group dynamics. The researchers joined the workshops as non-participant observers and leader training sessions as supervisorsand learning specialists.

Treatment in the experimental group: PLTL instruction

For an effective PLTL instruction, the processes before, during,and after the implementation were crucial for the study.

Gafney’s theoretical framework for implementing and evaluatingthe PLTL program (2001a, 2001b, 2001c) with six essential principleswas employed. These components were faculty involvement, integralto the course, leader selection and training, appropriate materials,appropriate organizational arrangements and administrativesupport. When PLTL has been properly implemented based onthese components, it offers a more positive gain in studentengagement, attitude, satisfaction, motivation, and academicperformance (Varma-Nelson et al., 2004; Gafney and Varma-Nelson, 2008). Therefore, these critical components were takeninto account in these processes and explained briefly.

Departmental and institutional support. To implement themodel, the first thing was to get approval from the administra-tion of the institution and the head of the department. Aftertaking their support, a search was conducted on how we couldhave inspired leaders to take part in this study. The universityhad a program called ‘‘Sharing the Success’’, which aimed toempower successful students to share their success by workingin an academic or administrative unit within the university.The role of these students was to assist the academic staff in theacademic units, train their peers, serve as a model for otherstudents and work on various projects in administrative units.Students having a minimum CGPA of 2.50 over 4.00 couldapply to the ‘‘Sharing the Success’’ programme. Each studentwho successfully completed the program by working at least40 hours would be given certificates of participation at the endof the academic term. Consequently, peer leaders, who com-pleted both the workshops and their training sessions success-fully throughout the semester, were awarded a Sharing theSuccess Program Certificate by the administration of the uni-versity at the end of the semester.

Integration of workshops to the course. Chemistry workshophours should be seen as important as other components of thecourse (lecture, laboratory); therefore, it was required all studentsattend fully and attendance was taken by the team leaders in eachworkshop. The workshops were coordinated with the content of thecorresponding week. Quizzes were added to assess students’individual progress in the chemistry concept and used to provideregular attendance at the workshops. The course instructor under-lined the importance of the workshops in lecture time andencouraged students to attend the workshops.

Course professor involvement. The general chemistry courseprofessor was in cooperation throughout the study especially inthe preparation of workshop materials and selection andtraining of peer leaders. For example, she examined the mate-rials, gave feedback and helped in revising the materials to thelast version because the content of workshop materials shouldbe overlapped with the course content and objectives. In theleader selection process, she helped to reach the sophomorestudents taking the course already and provided support to theleaders in their training.

Workshop materials. The content of the course and the timeneeded for them presented in the course syllabus were takeninto account by constructing the workshop materials. As indi-cated in Table 3, selected topics of general chemistry wereidentified and the course textbook was examined for these


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issues in order to write the learning objectives for each topic. Inthis direction, a booklet was prepared for use in the chemistryworkshop. Within each unit, the subject and subheadings ofthe subject and the corresponding learning outcomes werepresented. The workshop problems were prepared based onthe fact that problems should be enforcing the students at theappropriate level in a challenging way and encourage activeand collaborative learning at the same time (Strozak andWedegaertner, 2001). Many resources were utilized to constructproblems such as course textbooks and chemistry books, PLTLguidebooks, materials presented in dissertations, ACS and APChemistry exam questions, etc. Besides, their theoretical frame-work was established according to the concept of the ‘‘zone ofproximal development’’ proposed by Vygotsky (1978), and theydemonstrated as three parts in the booklet (1) individual reviewproblems that students would have completed before joiningthe workshop, (2) team learning problems to be solved incooperation with the peer leaders in the workshops, and (3)assessment problems to be solved individually after the work-shops to investigate students’ understanding and development.In the review section, the preliminary evaluation was conductedwith multiple-choice questions that students could solve ontheir own about the subject of the week. These materials weresupplied to the students before workshops. In Stewart et al.’s(2007) experience, if students take the material in a lecturebefore the workshop, they are so eager to learn and ready forPLTL instruction. Then, they continued with team problemswhich consisted of three or four open-ended problems beingsolved by a team under the guidance of a peer leader. Theseproblems were stepwise or structured problems which includedreflective problem solving, interpretation of graphs and data,inductive reasoning (moving from data to structures andmechanisms), and conceptual and critical thinking. Theygenerally had not been able to solve these problems alone,but with the help of peer leaders and social interaction betweenstudents, it was tried to increase the potentials of the students.After that, the students were given a quiz (individual problems),consisting of 1 or 2 multiple choice or open-ended questions,which are similar to team learning questions in order to assessindividual performance. For multiple choice questions, thecorrect answer was scored as 1 and an incorrect one was scoredas 0. For open-ended items, the rubric presented by Pyburnet al. (2014) was used to analyze the response in terms of itsscientific accuracy and its relationship with the question. Thus,full credit was scored as 2, and half credit was scored as 1, whileno credit was scored as 0. Feedback regarding individualproblems was also provided via team leaders. Students were

expected to be able to solve these questions individually aftergroup work. Their potential development was supported by alearning environment in which students were engaged in socialinteraction by challenging and reasonable activities.

Peer leaders. The selection and training of a peer leader is avery significant process for the proper implementation of themodel. In the selection process, the course instructor helped toidentify the sophomore students who completed the generalchemistry course successfully. After interviewing all potentialleaders from these students by taking into consideration theircommunication skills, 14 peer leaders, majoring in differentengineering departments, were selected. Two of them passed thegeneral chemistry course with CB but they showed enthusiasmabout this project and had good leadership and communicationskills. Others’ chemistry grade changed between AA and BB. Thenext step was to train leaders who were required to attend at least1.5 hour training sessions, which were held before discussingthe questions in chemistry workshops. Time arrangement wasmade according to their course schedule. Throughout thesetraining sessions, peer leaders were informed about leadershipskills, chemistry content knowledge, and pedagogical support,which were discussed in PLTL: A Handbook for Team Leaderswritten by Roth et al. (2001a, 2001b). Leaders received supportfor pedagogical information and social communication as wellas for discussing the workshop materials for that week whenthey met.

Related to the leadership skills, they learned about how theybecome effective leaders in their teams. For the pedagogicalsupport, the researcher gave a brief training on learningtheories and styles related to PLTL, learning differences instudents, motivation, ethics, teaching strategies and tools suchas analogy, paired problem solving, flowcharts, and round-robin. Leaders were expected to select and apply the appro-priate teaching strategy and tool in each topic according to thecontent and student profile in their team. Finally, the contentknowledge related to the workshop problems was the mainissue in the training session, and nearly seventy-five percent ofthe time was spent on the understanding of the subject matter.For each session, leaders worked the chemistry problems of thenext workshop in groups and covered each concept before thecorresponding workshop. The answer key was not given topeer leaders or students as emphasized in the PLTL model(Varma-Nelson and Coppola, 2005). Since it was very importantto understand their role in this study, it was stressed that theyshould behave as guides or facilitators rather than as teachers.

Organizational arrangement. The organizational arrange-ment of the PLTL program was vital and should be handled

Table 3 Workshop programs

Workshop Topics

Workshop 1 Electronic Structure of Atoms/Periodic Properties of the ElementsWorkshop 2 Basic Concepts of Chemical BondingWorkshop 3 Molecular Geometry and Bonding Theories/GasesWorkshop 4 Liquids and Intermolecular Forces/Solid and Modern MaterialsWorkshop 5 Thermochemistry/ThermodynamicsWorkshop 6 Chemical Kinetics


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before the implementation especially related to issues of time,group size, location, and teaching resources for providing aneffective discussion environment. Thus, firstly, the workshopswere arranged to be operated during class time. One lecturesession (50 minutes) of three teacher-centered lectures wastransformed into a chemistry workshop and 20 minutes wereadded to this session, so students participated in total 70 minutespeer-led chemistry workshops once in two weeks as part of thecourse during the study. The twenty-minute difference is due to thearrangement of the classroom setting and distributing the coursematerial to the groups.

A workshop group generally consisted of four to six studentsplus a peer leader so the average size was five students pergroup. Students’ gender, success, and major were also takeninto account when the teams were formed. As a result, aheterogeneous structure was created by ensuring that eachteam had students from all departments, both gender anddifferent achievement levels, based on entrance scores to theuniversity (LYS scores). The workshops were conducted in thestudent study hall in the engineering building so they werefamiliar with the location and had the opportunity to study as ateam because of its physical structure.

Peer-led chemistry workshops

At the beginning of the term, students enrolled in the coursewere assigned to groups of 6 or 7 students and each group isassigned a number ranging from 1 to 14 and a guiding teamleader. Firstly, leaders were trained on the content knowledgeand content specific pedagogic knowledge to have necessarybackground information to handle problems easily. Then, afterthe content was discussed in the course, students worked withtheir group members in every workshop in the student studyhall under the guidance of their leaders to solve the assignedproblems. During the semester, six workshops were conducted,and the topics are given in Table 3. At the workshops, eachleader wore an identification card that showed their name andtitle as a leader. Also, peers wrote their names in a name taguntil leaders learned their names and took attendance. Later,leaders started discussing the team problems by means of theteaching techniques taught in the leader training. In thissection, leaders gave time to their peers to read and analyzethe problems, and then asked some questions to the studentsand guided them with the tips on how to solve them. It wasexpected that they were influenced by each other and reached aconclusion with the feedback from their leaders. The under-standing of the problem for each peer within the given timeperiod was checked by the leaders. Finally, after all materialswere discussed, each leader distributed a quiz related to thetopic and gave 10 minutes to answer the questions individually.The workshops and leader training sessions took place simulta-neously and continued throughout the semester.

Treatment in the control group: TCI

The first section of the CEAC 105 course was taken as a controlgroup in this study. This group was taught using traditionalcollege instruction (TCI) with weekly three 50 minute lecture

periods and a three laboratory hour once a two week but theydid not attend the workshops. In the lecture, the same professorteaches the contents like what she did in the experimental group(PLTL). Hence, both groups had the same teacher-centeredinstruction in the lecture by the course professor who startedintroducing the concepts and then solved some exercises. Thelecture hour in the control group was longer so the instructorsolved more problems individually and students followed her towrite the notes to their notebooks. The methods used here weremainly lecturing, questioning by the teachers and sometimesdiscussions between a few students and teachers.

Data analysis

To evaluate the effect of the implementation, quantitative dataanalysis was conducted in terms of descriptive and inferentialstatistics using IBM Statistical Package for the Social Sciences(SPSS) 24. All variables and subjects were controlled in terms ofmissing values. The missing value was 3.9% for Pre-GCCT,and 9.4% for Pre-STAI-S, Pre-SAQ, and LYS scores. Dealingwith missing data in pre-tests, a dummy variable adjustment(Allison, 2001) was carried out. Since there was no evidence tohave a pattern of missing values in pre-tests, the missing valueswere replaced with a series of means. Furthermore, descriptivestatistics were presented as scores of experimental and controlgroups’ means and standard deviations. For the inferential statis-tics, one-way multivariate analysis of covariance (MANCOVA) wasperformed to determine the effect of PLTL over TCI (independentvariable of the study) on students’ conceptual understanding ofgeneral chemistry concepts, situational anxiety and social anxiety(dependent variables of the study) after controlling some pre-existing differences due to pre-test scores, trait anxiety scores anduniversity entrance examination scores (covariates). Additionally,all variables were checked for assumptions of MANCOVA, whichwere sample size, normality, outliers, linearity, multicollinearity,the homogeneity of variances, the homogeneity of regression, andthe reliability of covariates, and they were met. All statisticalanalyses were conducted at the 0.05 significance level.

Results and discussion

The analysis concerning descriptive statistics for the pre-testscores and potential covariates was performed for both experi-mental and control groups. Table 4 summarizes these descrip-tives. Furthermore, descriptive statistics for the post-tests werepresented in Table 7. The determination of covariates and theeffects of treatment on both collective dependent variables and

Table 4 Descriptive statistics for pre-tests

Tests N

TCI

N

PLTL

Mean SD Mean SD

LYS 60 296.7 39.92 68 293.71 39.84STAI-T 60 44.40 11.08 68 42.60 11.90Pre-GCCT 60 5.27 3.40 68 5.10 3.25Pre-STAI-S 60 48.04 6.11 68 49.85 8.01Pre-SAQ 60 92.60 13.75 68 97.38 15.29


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each dependent variable were also discussed in further sectionsrespectively.

Determination of covariates

If there are pre-existing differences between groups, we cannotconclude that the difference was due to the intervention effect. Forthis reason, Tabachnick and Fidell (2013) emphasized that it wasneeded to determine potential covariates that are significantlycorrelated with dependent variables. The possible covariates inthe study were Pre-GCCT, Pre-STAI-S, Pre-SAQ, Pre-STAI-T, and LYSscores. Because a majority of the participants were freshmanstudents, they did not have GPA. Therefore, university entrancescores (LYS scores) of the students were obtained to adjust the pre-existing difference in their achievement.

Prior to main analysis, correlation analysis was performed tocheck whether they were appropriate to be used as covariates.The assumptions of correlation analysis (the level of measure-ment, related pairs, normality, linearity, and homoscedasticity)were satisfied before the analysis. According to the results ofcorrelation indicated in Table 5, LYS, STAI-T, Pre-GCCT, andPre-STAI-S were significantly correlated with at least one of thedependent variables (Post-GCCT, Post-STAI-S, and Post-SAQ) sothey were suitable to be used as covariates.

Effect of treatment on collective dependent variables

After satisfying all the assumptions, one-way between-groupMANCOVA was run for testing the research question of thestudy at a 0.05 significance level. Table 6 depicts the MANCOVAresults of the study.

The results revealed that there was a statistically significantmean difference in post-test scores between PLTL and TCI withrespect to the combined dependent variables of conceptualunderstanding, state anxiety, and social anxiety in the generalchemistry course after controlling the effect of LYS, STAI-T, Pre-GCCT and Pre-STAI-S scores: F(3, 120) = 5.77, p o 0.05, Wilks’

lambda = 0.764. The observed power was with a high value of0.940. Besides, partial eta squared and Cohen’s d values werefound to be 0.126 and 0.76, respectively, indicating a nearlyhigh magnitude of the difference among the groups (Cohen,1988; DeCoster, 2012).

This indicates that 12.6% of the multivariate variance oncollective dependent variables was associated with the treat-ment effect. These results showed that the difference betweenthe PLTL group and TCI groups resulted from the effect oftreatment and this difference had practical importance.

Based on the results given in Table 6, there is no statisticallysignificant contribution of the pre-test scores of the GeneralChemistry Concept Test (F(3, 120) = 1.46, Wilk’s lambda =0.965, p o 0.05) and the pre-test scores of state anxiety (F(3,120) = 2.05, Wilk’s lambda = 0.951, p o 0.05) to their combineddependent variables. In contrast, students’ trait anxiety scores(F(3, 120) = 5.77, Wilk’s lambda = 0.764, p o 0.05) and LYSscores (F(3, 120) = 2.68, Wilk’s lambda = 0.937, p o 0.05) weresignificant contributors of their combined dependent variables.

Effect of treatment on each dependent variable

A follow-up ANCOVA was conducted in order to determine theeffect of treatment on each dependent variable. The descriptivestatistics of dependent variables for both groups are presentedin Table 7. Accordingly, the mean differences between groupsare slightly different from each other with respect to conceptualunderstanding (MCG = 9.23, SDCG = 3.38, MEG = 9.53, SDEG =3.15) and much different with respect to state anxiety (MCG =45.03, SDCG = 11.57, MEG = 42.54, SDEG = 12.69) and socialanxiety (MCG = 82.30, SDCG = 21.11, MEG = 87.03, SDEG = 19.29).

The results of multiple univariate ANCOVAs are displayed inTable 8. Before checking the p values, firstly, Bonferroni’sadjustment was applied to the alpha value by dividing 0.05 bythe number of dependent variables (3) to decrease Type I errorin the separate univariate analysis (Tabachnick and Fidell,2013). Consequently, treatment had a significant main effecton all dependent variables based on the new adjusted alphalevel of 0.017. The findings given in Table 8 indicated astatistically significant mean difference in students’ conceptualunderstanding between the PLTL group and the TCI group infavor of PLTL when LYS, STAI-T, Pre-GCCT and Pre-STAI-S werecontrolled (F(1, 122) = 5.378, p o 0.017). The adjusted meanscores of the General Chemistry Concept Post-test in Table 6pointed out that the students in the PLTL group had signifi-cantly higher mean scores (Madj = 9.60, SE = 0.38) than those inthe TCI group (Madj = 9.14, SE = 0.40). In other words, the PLTLgroup performed better in the General Chemistry Concept Test.The guidelines proposed by Cohen for eta squared can also beimplemented for interpreting the strength of partial etasquared where 0.01 is considered small, 0.06 is medium and0.14 is large (Pallant, 2011). The partial eta squared value forconceptual understanding was found to be 0.081, which meansmedium effect size. This value implied that the proportion ofvariance in the students’ conceptual understanding explainedby the treatment was 8.1%. Similarly, Cohen’s d value was alsocalculated as the medium effect size of 0.59 for conceptual

Table 5 Correlations between potential covariates and dependentvariables

Post-GCCT Post-STAI-S Post-SAQ

LYS 0.195* �203* �135STAI-T �0.178* 0.768** 0.181*Pre-GCCT 0.193* �0.100 0.046Pre-STAI-S �0.210* 0.053 0.140Pre-SAQ �0.029 �0.160 0.059

Note: *Correlation is significant at the 0.05 level (2-tailed). **Correla-tion is significant at the 0.01 level (2-tailed).

Table 6 Results of one-way MANCOVA for collective dependentvariables

EffectWilks’lambda F df

Errordf Sig.

Partial etasquared

Observedpower

STAI-T 0.591 57.75 3 120 0.000 0.591 1.000LYS 0.937 2.68 3 120 0.050 0.063 0.641Pre-GCCT 0.965 1.46 3 120 0.229 0.035 0.378Pre-STAI-S 0.951 2.05 3 120 0.110 0.049 0.515Treatment 0.764 5.77 3 120 0.000 0.126 0.998


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understanding (Cohen, 1988; DeCoster, 2012). The power valuewas also found to be 0.835. Consequently, it can be implied thatthe difference among the groups arose from the treatmenteffect and had practical significance.

These findings supported that the PLTL model is likely tolead to better conceptual learning in the general chemistrycourse than traditional college instruction (TCI) did. Therefore,the current study provides further empirical support for pre-vious studies showing the effectiveness of peer-led team learn-ing over traditional instruction (Cracolice and Deming, 2004;Varma-Nelson and Coppola, 2005; Gafney and Varma-Nelson,2008; Bramaje and Espinosa, 2013). The probable underlyingcauses that PLTL instruction was effective in improvingstudents’ conceptual understanding in general chemistry canbe related to the characteristics of the model. Cracolice andDeming (2004) state that the PLTL model provides an environ-ment where students can have the opportunity to become activeparticipants in their learning process. For example, studentseasily asked questions, worked together and discussed andnegotiated the ideas in the PLTL group of this study. Suchactive learning environments can help students to gain a deeperunderstanding of the subject matter, thus promoting the levelof student meaningful learning (Duit and Treagust, 2003; Duitet al., 2008). Additionally, the reasoning ability and problem-solving skills might have played a role in the difference betweenthe PLTL and the TCI group in terms of students’ understandingof concepts.

Deming et al. (2003) point out that there is a significantdirect relationship between the reasoning ability and students’capacity to solve conceptual problems in general chemistry.Since students are challenged to use their problem-solvingskills, thinking skills, and reasoning abilities in PLTL work-shops, they are able to improve their reasoning abilities anddevelop strong conceptual understanding (Cracolice and Dem-ing, 2004).

Although the PLTL approach had a significant positiveimpact on conceptual understanding, the magnitude of themean difference among the groups was not as much as expected.This less effective outcome may result from the duration of the

PLTL workshops. The suggested length of the workshop time isweekly 90–120 minutes (Gafney and Varma-Nelson, 2008). How-ever, in this study, the workshop took place biweekly and lasted70 minutes. Gafney and Varma-Nelson (2008) claim that ifworkshops are implemented in a shorter time than the recom-mended duration such as 60 or 75 minutes, the same effect onstudent performance as longer ones cannot be observed.

Another significant mean difference was detected betweenPLTL and TCI in terms of students’ state anxiety after control-ling LYS, STAI-T, Pre-GCCT, and Pre-STAI-S, F(1, 122) = 4.665,p o 0.017. The adjusted mean scores on the state anxiety post-test indicated significantly lower mean scores in the PLTLgroup (Madj = 43.26, SE = 0.95) compared to the TCI group(Madj = 42.22, SE = 1.02). This means that the PLTL group had alower level of state anxiety than the TCI group. The partial etasquared value was found to be 0.071, which means mediumeffect size and the value of power was found to be 0.776,suggesting that treatment leads to a meaningful effect onstudents’ anxiety. Besides, Cohen’s d value was also calculatedas the medium effect size of 0.55 for state anxiety (Cohen, 1988;DeCoster, 2012). Consequently, it can be implied that alongwith increasing students’ conceptual understanding, the PLTLmodel appears to be an effective way of decreasing students’anxiety. This finding might support the fact that while studentsfeel anxious, threatened, or stressed in lecture hours, they feelmore relieved, comfortable and content in a PLTL workshopenvironment which focuses on the supportive and small-groupdiscussion under the guidance of a peer leader instead ofa course instructor or assistants, as stated by Gafney andVarma-Nelson (2008). In other words, students may feel morecomfortable about sharing their ideas in smaller peer groupsthan speak up in front of the whole class. On the other hand,the result is inconsistent with the findings of Chan and Bauer(2015) who report no significant difference in students’ anxietybetween students of the PLTL group and students of the non-PLTL group (alternative learning activities: self-organized studygroup, instructor-led review sessions, drop-in tutorials led bygraduate or undergraduate chemistry majors, and instructoroffice hours) and a slightly significant increase in students’anxiety and fear of chemistry throughout the semester.

Finally, the results of the follow-up ANOVA revealed thatafter adjusting LYS, STAI-T, Pre-GCCT and Pre-STAI-S scores,there was a statistically significant mean difference in students’social anxiety among the groups, F(1, 122) = 7.060, p o 0.017,and partial eta squared = 0.104. The adjusted mean scores ofthe students in the PLTL group (Madj = 87.02, SE = 2.42) werehigher than those in the TCI group (Madj = 82.31, SE = 2.58) with

Table 7 Descriptive statistics for post-tests

Tests N

TCI

N

PLTL

Mean SD Adjusted mean SE Mean SD Adjusted mean SE

Post-GCCT 60 9.23 3.38 9.14 0.40 68 9.53 3.15 9.60 0.38Post-STAI-S 60 45.03 11.57 44.22 1.02 68 42.54 12.69 43.26 0.95Post-SAQ 60 82.30 21.11 82.31 2.58 68 87.03 19.29 87.02 2.42

Note: SE: standard error.

Table 8 Results of follow-up ANCOVAs

SourceDependentvariable F Sig.

Partial etasquared

Observedpower

Treatment Post-GCCT 5.378 0.006 0.081 0.835Post-STAI-S 4.665 0.011 0.071 0.776Post-SAQ 7.060 0.001 0.104 0.924


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regard to the social anxiety post-test. The power value was0.924. In addition, the partial eta squared value of 0.104emphasizes the strong and meaningful difference among thegroups due to the effect of treatment. Also, Cohen’s d value wasfound to be 0.68, which indicates medium effect size for socialanxiety (Cohen, 1988; DeCoster, 2012). From this result, it canbe claimed that although the PLTL model assisted students toimprove their conceptual understanding of general chemistryconcepts and reduce situational anxiety, it was not successful indecreasing students’ social anxiety. This negative result wassurprising and it contrasts with the study of Johnson andJohnson (1994) that advocates the advantages of collaborativesmall group work on students’ self-esteem and social skills.

However, the reason why PLTL instruction was not effectivein alleviating students’ anxiety about social situations may beexplained by the fact that control group students did notparticipate in any other activity. Therefore, they did not engagein any situation which causes them to express themselves,and explain some ideas and knowledge as a member of anysocial group consisting of opposite sex and relative strangers.Furthermore, the treatment was applied only for one semesterso students from the PLTL group met only six times. As a result,students may see the group work as a new experience orchallenge for them and need time to get used to workingtogether with other students and overcome any problems thatoccur in the group. It is possible to get a more accurate result byexamining the effect of the PLTL model on social anxiety after along-term practice. In addition, since the biweekly schedule ofworkshops, the students generally tried to handle the conceptsof two chapters during one workshop so they concentrated onproblem-solving and learning new information. The dialoguebetween students and a leader was commonly much more com-pared to social interaction and dialogue between students. In thattime, they discussed and solved the problems, and continued withthe next questions. Thus, the ability to interact with each other maynot be well established in order to develop strong relationships andinterpersonal skills. For such reasons, the students in the PLTLgroup may not have overcome social anxiety.

Conclusion

In conclusion, the current study approves and expands manyfindings related to the effectiveness of a relatively new evidence-based approach, peer-led team learning, on students’ concep-tual understanding in the context of undergraduate generalchemistry after controlling their LYS score, trait anxiety scoreand pre-test score of the General Chemistry Concept Test andstate anxiety. This study also sustains a body of evidence thatthe PLTL model is better to alleviate students’ situationalanxiety in general chemistry, while it is not effective at reducingsocial anxiety when compared to traditional college instruction(TCI) after adjusting those variables. Accordingly, the results ofthis study support the chemistry education literature in such away that PLTL can be implemented in postsecondary chemistryclasses to promote the cognitive and affective development of

students despite its adverse effect on social anxiety. A long-termsuccessful application of the PLTL model may help students toease their social anxiety because team leaders get more experi-ence with time and can create a more productive environmentfor students to develop and sustain positive social interactionswith their peers.

This study has several implications for educators andresearchers not only in chemistry but also in other STEMcourses. Based on the literature about effective college teachingand learning, it is clear that evidence-based teaching strategiesemphasizing active and collaborative instruction are moreeffective in fostering deep and meaningful learning than tradi-tional instruction (Kuh et al., 2005; Pascarella and Terenzini,2005). Peer-led team learning, as an evidence-based teachingstrategy, enables students to involve themselves actively inthe learning process through working as a team under theguidance of a peer-leader. The present study provides not onlyevidence about the instructional effectiveness of the PLTLmodel on the conceptual understanding of general chemistrybut also sufficient information regarding six essential principlesfor the adaptation of PLTL in other STEM courses. Consequently,this study can be used as a guideline for college teachers todesign more effective instruction in STEM courses, particularlyin a general chemistry context.

It is important to note that students’ affective developmentis as significant as their cognitive development since they have animpact on students’ learning too (Chandran et al., 1987; Rennieand Punch, 1991; Berberoglu and Demircioglu, 2000; Osborneet al., 2003). If students are anxious, nervous, and uncomfortablein a classroom environment, they are unlikely to participate activelyin their learning process, and thus, such a situation can influencetheir performance negatively. According to the findings of thisstudy, instructors can lessen their students’ anxiety with theimplementation of peer-led chemistry workshops in which stu-dents feel more comfortable through collaborative teamwork.

Related to the limitations, the study was performed in onlyone semester. In addition, participants were not selected byrandom sampling; instead, groups did. This can be a problem forthe independence of observation because they were instructed withdifferent teaching methods as a group within a classroom, and inthe PLTL group, students were working in small groups (Gravetterand Wallnau, 2007; Stevens, 2009). Consequently, they were likelyto interact with each other in some way, and each member of thegroup may have influenced the general chemistry performance oranxiety level of all other group members. Therefore, depending onthe extent of the dependence of observations, this study maypresent inflated estimates of effect sizes and deflated estimates ofp-values. Besides, it was tried to minimize the threats to the internalvalidity of the results by controlling some extraneous variables inthe study.

To sum up, not only for the US context but also for many othercountries, initiatives to improve the quality of education at thetertiary level are more limited when compared to other levels. Thisstudy is one of the first systematic attempts to test the impact of thePLTL model on cognitive and affective aspects in the context wherethe study is conducted. The findings promise benefits of the model


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for improving conceptual learning while alleviating state anxiety infreshman students in General Chemistry.

Conflicts of interest

There are no conflicts to declare.

AppendixSample items of the GCCT

A 100 g sample of a metal was heated to 100 1C and then quicklytransferred to an insulated container holding 100 g of water at22 1C. The temperature of the water increased to reach a finaltemperature of 35 1C. Which of the following can be concluded?‡

(a) The metal temperature changed more than the watertemperature did; therefore the metal lost more thermal energythan the water gained.

(b) The metal temperature changed more than the watertemperature did, but the metal lost the same amount ofthermal energy as the water gained.*

(c) The metal temperature changed more than the watertemperature did; therefore the heat capacity of the metal mustbe greater than the heat capacity of the water.

(d) The final temperature is less than the average startingtemperature of the metal; therefore the total energy of the metaland water decreases.

(e) The final temperature is higher than the average startingtemperature of the water; therefore the total energy of the metaland water increases.

According to Pauling’s electronegativity scale, the electro-negativity of hydrogen is 2.1 and the electronegativity of chlor-ide is 3.0. What is the type of bond between hydrogen andchloride in hydrogen chloride, HCl. (1H, 1A; 17Cl, 7A)

(a) ionic bond(b) covalent bond*(c) hydrogen bond(d) metallic bondWhat is the reason for your answer to the previous question?(a) The hydrogen atom and chlorine atom each share one

electron in the compound.*(b) Hydrogen is bonded to highly electronegative atoms such

as F, Cl and O(c) HCl is a strong acid, and it decomposes to its ions when it

dissolves in water(d) Hydrogen transfers one electron to chlorine to form a

compound.The correct answer is presented with an * sign.

Acknowledgements

We would like to thank to CEAC faculty members, head of thedepartment, Prof. Seniz Ozalp-Yaman, and each team leader fortheir continued support throughout the project.

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