Research Strategies

Chapter 6

Research steps

Literature Review• identify a new idea for research, • form a hypothesis and a prediction,Methodology • define and measure your variables, • sampling • how to treat them ethically, • the next step is to select a research strategy

Definitions of Quantitative and Qualitative Research(Creswell)

Quantitative Research A type of research in which the

researcher decides what to study; asks specific, narrow questions; collects quantifiable data from participants; analyzes these numbers using statistics; and conducts the inquiry in an unbiased, objective manner.

Qualitative Research A type of research in which the

researcher relies on the views of participants; asks broad, general questions; collects data consisting largely of words (or text) from participants; describes and analyzes these words for themes; and conducts the inquiry in a subjective, biased manner.

The term quantitative refers to the type of data or variables that this research examines

Strategies, Designs, and Procedures

types, srategies, designs, and procedures

• The process of developing a research study can be broken down into three distinct stages: determining a research type, research strategy, determining a research design, and determining research procedures.

Research Strategies

The 5 basic research strategies are • the experimental strategy• the quasi- experimental strategy• the non-experimental strategy • the correlational strategy • the descriptive strategy.

Research Design,It is not enough to say the design is experimental or correlational

•Group versus individual •Same individuals (within subjects) versus different individuals (between subjects)•The number of variables to be included

Research Procedures

• Exactly how the variables will be manipulated, regulated, and measured.

• Exactly how many individuals will be involved. • Exactly how the individual participants or

subjects will proceed through the course of the study.

Internal and external validity

• Internal validity of a research study is the degree to which the study accurately answers the question it was intended to answer.

• External validity refers to the extent to which we can generalize the results of a research.

Threats to external validity

External validity• There are at least three different kinds of

generalization, and each can be a concern for external validity.

• Generalization from a sample to the general population.

• Generalization from one research study to another one.

• Generalization from a research study to a real world situation.

Threats to external validity

Category 1: Generalizing Across Participants or Subjects

Selection bias 1. Local samples2- College students3- Volunteer bias4- Participants characteristics (gender, age)

Category 2: Generalizing Across Features of a Study

• Novelty effect• Multiple treatment interference (extra

treatment)• Experimenter characteristic (gender, race,

personality, ability)

Category 3: Generalizing Across Features of the Measures

• Sensitization ( the treatment works only if subjects are pre-tested, it is the measurement that works not the

treatment)• Measurement (the results of the study may be limited to

a specific measurement)

• Time of measurement (how long after treatment it is

measured)

Threats to internal validity

A. Extraneous Variables

Any variable in a research study other than the specific variables being studied is an extraneous variable.Every research study has thousands of them.

for example, some participants may be tested in the morning and others in the afternoon. (some people perform better in the afternoon)or part of the study may be conducted on a dark and cloudy Monday and another part on a sunny Tuesday. (some people perform better on Mondays)

B. Confounding variables

is an extraneous variable ( usually unmonitored) that changes systematically along with the two variables being studied.

•EX Var = Type of background music and problem solving performance •Con Var = one group of students were hungry.

C. Time- Related Variables

1- History (Value Added-Rich schools)2- Maturation (Children, can change in a

relatively short time).3- Instrumentation (the researcher doing the

observing may become more proficient in making the observations in the posttest)

4- Testing effects ( practice, fatigue, and carry- over effects)

• Posttest was better just because they practiced many times in repeated measures

• Posttest was worse because they were tired

Time- Related Variables

5- Regression toward the mean: (extreme scores on one measurement tend to be less extreme on a second measurement)

Blood pressureCostco

D. Other Threats

• Compensa tory equalization• Compensation rivalry• Resentful demoralization

Threats

Compensatory equalization; the comparison group is somehow compensated by

others in order to make up for the fact that they are not receiving a treatment

Goal: effectiveness of access to science lab

Compensation: the other group uses a simulation

Knee pain

Threats

Compensation rivalrywhen the comparison group knows what the program

group is getting and therefore, develops a competitive attitude with them.

John Henry effect--John Henry was a steel-driver who outperformed a machine (steam-hammer) under an experimental setting because he was aware that his performance was compared with that of a machine.

Threats

Resentful demoralizationwhen the comparison group knows what the program

group is getting and get discouraged or angry and withdraw from the study.

Threats to Both Internal and External Validity

• Experimenter bias (results obtained in a study may be specific to the experimenter who has the expectations)

• Demand Characteristics and Participant Reactivity (cues given about the hypothesis & 4 types of

human subjects)• Exaggerated Variables (70 degrees vs. 120 degrees

classrooms)

Group Discussion 1

• Explain the difference between assignment bias and selection bias. Which one is a threat to internal validity and which is a threat to external validity?

• A researcher wants to evaluate the effectiveness of a new teaching method. He randomly selects two 6th grade classes in Long Beach. One class is taught with the traditional method (Method A) and another class is taught using the new method (Method B). Both classes are taught by the same teacher, using the same pretest and posttest. Explain what type of research is this and what are the possible external and internal threats to validity of this research?