Chapter 5,Suter

Constructs

Abstract, an idea

•Presumed to exist

•Can’t be seen or even directly measured (it doesn’t really exist – it’s a presumption!)

character, anxiety, intelligence, athleticism, persistence, leadership, aggression, love, honesty

How, then, do we have a discussion about it, learn about it, or teach it?

Operational definitions

Once a term or construct has been operationally defined there is no ambiguity about how to define it or measure it.

Allows standardization, consistency

Allows discussion

Allows empirical measurement

Variables & Constants• Variables (often operationally defined

constructs) – Will have two or more values (height, gender,

grades, humor, time)

– Can have “more” or “less” – Can belong to one category (group) or

another (categorical variables)

• Constant – unchanging value of a characteristic

Variables in Research

• Independent

• Dependent

• Attribute

• Extraneous

• Confounding

Independent Variable (IV)“the value is free to vary” – well, sort of.In experimental research, the researcher

controls the value of the IV and determines the structure of the experiment and the values of the IV.

example

Creating two groups within an experiment1. Students in a New Reading Program2. Students in the Old Reading Program

Dependent Variable (DV)

• The value is “dependent” upon the IV

• A student’s reading performance will be determined or dependent upon which reading program the student participates in.

Independent & Dependent Variables “work together”

• Researcher presumes (e.g., hypothesizes) the (IV) has an effect upon another variable

• The relationship between the IV and DV is stated in the hypothesis (and research question.)

Independent/Dependent Variables

• Cause and Effect” relationship (e.g., the IV “causes” the DV)

• Experimental studies– The research can vary the amount of an IV to

test it’s effect upon the DV. Manipulates• Group assignment• Reinforcement or praise• Amount of time

Characteristics of IV

• True IV: random assignment to groups

• Quasi IV: non-random assignment

Example:New Reading Program going to be used by Ms. Smith 3rd graders.

Same Old reading program to be use my Mr. Jones 3rd graders.

Question: Random assignment or not?

Experimental &Treatment groups

The group that is receiving the “new” program, is the “treatment group.

The group this is receiving the “old” program, is the “control” group.

Better yet, the control group would be a group that receives NO program. (Maybe students would learn to read better without any program!)

Controlled vs Extraneous• IV is manipulated or controlled by the

research.

• Other variables the research has no control over: gender, SES, anxiety, weather, student absences, parental influences, time of day, teacher illness

• More you can hold constant the better off you are

Attribute and Extraneous V

Alternative explanations for the results

Gender may have influenced the DV.

Construction going on outside the window may have influenced the DV.

Goal of experimental control (e.g., strict use of the experimental method) is to reduce the number of alternative explanations

Attribute and Extraneous V

Goal of experimental control is to reduce the number of alternative explanations

Attribute variables are pre-existing variables that cannot be altered and may have an influence: gender, SES, age

Extraneous variables are variables that the researcher can attempt to control: time of day program is conducted, comfort in classroom, teacher, IQ level of students, prior experience or knowledge.

Confounding V

Another alternative explanation for the results.

Unexpected or unanticipated

When two or more variables interact: e.g., gender & anxiety, time of day and interest, teacher and gender

Hypothesis

• A hypothesis predicts the existence of a relationship between two variables– The IV and the DV– Is embedded in the Research Question– Specifically names or identifies the predicted

relationship

Research Hypothesis

• 3rd grade students who learn Covey’s 7 Habits will improve their reading comprehension over the year as measured by the ISAT more than 3rd grade students who don’t learn Covey’s 7 Habits.

• RQ: Will 3rd grade students who learn Covey’s 7 Habits improve their reading comprehension over the year as measured by the ISAT more than 3rd grade students who don’t learn Covey’s 7 Habits?

Research Hypothesis

• If 3rd grade students learn Covey’s 7 Habits, then they will improve their reading comprehension over the year as measured by the ISAT more than 3rd grade students who don’t learn Covey’s 7 Habits.

Research Hypothesis

• 3rd grade students who learn Covey’s 7 Habits will improve their reading comprehension over the year as measured by the ISAT more than 3rd grade students who don’t learn Covey’s 7 Habits.

• RQ: Will 3rd grade students who learn Covey’s 7 Habits improve their reading comprehension over the year as measured by the ISAT more than 3rd grade students who don’t learn Covey’s 7 Habits?

Dr. Shinn’s Aside• Directional H – predicts the “more/less” outcome

of manipulating the IV– Participation or no participation in an after

school reading program improves reading comprehension

• Nondirectional H - no prediction of “more/less”– The reading comprehension of students who

participate in an after school reading program will differ from the reading comprehension of students who do not participate in the program.

Alternative Hypothesis

• The IV did not determine the DV (or the DV was not dependent upon the IV).

• Another explanation can be offered.

• If teachers who use the 7 Habits then they will be more enthusiastic and be better teachers than teachers who don’t use the 7 Habits.

Null Hypothesis

• Experiment• Scientific Method• Statistics

• The hypothesis that is tested is the NULL Hypothesis – that NO differences exist between the groups

• Or• That NO relationship exists between Variables

Null Hypothesis• 3rd grade students who learn Covey’s 7 Habits will improve their

reading comprehension over the year as measured by the ISAT more than 3rd grade students who don’t learn Covey’s 7 Habits.

• Null H: 3rd grade students who learn Covey’s 7 Habits will not improve their reading comprehension any more or less over the year as measured by the ISAT more than 3rd grade students who don’t learn Covey’s 7 Habits.

• There is NO difference between using 7 Habits than not using them.

• Advantages of using a Hypothesis:– Helps our understanding because we must be

able to identify the IV and the DV– Forces one to consider the nature of the

relationship between the IV and the DV– Testing hypotheses add to the body of

knowledge – whether supported or not.• In theory validation – a theory makes predictions

as the predictions (H’s) are tested the theory is validated (or not).

Dr. Shinn’s Aside

End chapter 5

Hypothesis• Disadvantages

– Bias - look only for that data the supports our hypothesis

– Inadvertently set up the study to help our prediction (e.g., give Ms Smith, the best teacher, assign her Method A)

– Overlook important but unintended results or dynamics (e.g. Hawthorne effect)