Research Design

Question 1

Mediating Variable

Answer 1

Responsible for the relationship between variables

IV affects the mediator, then mediator affects dv

Question 2

Moderating Variable

Answer 2

Affects the direction and strength of the relationship between the IV and DV

Question 3

Quasi-Experimental vs True Experimental research

Answer 3

True experiment = random assignment

Quasi-experiment = pre-existing groups or single group *NO CONTROL of assignment of subjects

Question 4

Simple Random Sampling

Answer 4

Every member of population has equal chance of being selected (random)

Selection of one member has no effect on selection of another member of the population

Reduces bias

Question 5

Stratified Random Sampling

Answer 5

Population varies in terms of the characteristics
(E.g. gender, age, education level, SES etc.)

Divide population and randomly sample each statrum

Question 6

Cluster Sampling

Answer 6

Sample from clusters of individuals when unable to access to entire population of interest

E.g., random selection of patients from 10 inpatient programs

Question 7

Confounding Variable

Answer 7

Extraneous/irrelevant variable that introduces Systematic error

Threatens internal validity of research design

Question 8

Ways to Limit the Effects of Confounds

Answer 8

Random assignment

Hold extraneous variable constant

Match subjects on extraneous variable

Include extraneous variable as additional IP (blocking)

Statistical control via ANCOVA

Question 9

Systematic vs. Random Error

Answer 9

Systematic = confounding variable

Random error = unpredictable fluctuations in subjects/condition/measuring instruments

Question 10

Internal and External Validity

Research, not psychometrics

Answer 10

Internal Validity = there is a causal relationship between IV and DVs

External Validity = the causal relationship generalizes to other people, settings, times, and operations

Question 11

Threats To Internal Validity: Extraneous Variables

Answer 11

Maturation (examinee)

History (external events)

Testing / Practice effects

Instrumentation

Regression toward the mean

Selection (assignment)

Attrition

Question 12

***Threats To External Validity

Answer 12

Testing / Treatment Interaction

Selection / Treatment Interaction

Reactivity

Multiple Treatment Interference (carryover effects)

Question 13

Reactivity: Evaluation Apprehension

Answer 13

Subject changes their behavior in order to avoid negative evaluation

[Threat To EXTERNAL Validity]

Question 14

Reactivity: Demand Characteristics

Answer 14

Cues in experimental setting that:

• Inform subjects of the purpose of the study
• Suggest what behaviors are expected

[Threat To EXTERNAL Validity]

Question 15

Reactivity: Experimenter Expectancies

Answer 15

Experimenter unintentionally provides subjects with cues (demand characteristics)

Experimenter behavior that leads to biased results

[Threat To EXTERNAL Validity]

Question 16

Ways to Limit Effects of Reactivity

Answer 16

Deception

Single-or Double-blind technique

Unobtrusive measures

Question 17

Multiple Treatment Interference:

Carryover Effects

Answer 17

When different levels of IV affect one another

Order effects

Practice effects

[Threat To EXTERNAL Validity]

Question 18

Between-Group Designs

Answer 18

Different levels of IV administered to a different group or subject

Simplest: one IV with two levels and two groups

Question 19

Between-Groups: Factorial design

Answer 19

2+ IV’s

Allows for analysis of Main effects and Interaction Effects

e.g. two-way ANOVA, three-way ANOVA

Question 20

Between-Groups: Main Effect

Answer 20

Effect of one IV on the dv

*disregards effects of all other IV’s

Question 21

Between-Groups: Interaction

Answer 21

Interaction occurs when the effects of an IV differ at different levels of another IV

e. g. effects of intervention levels differ for different sx severity levels
* When there is an interaction, main effects must be interpreted in light of interaction

Question 22

Within-Subjects Designs (Repeated Measures)

Answer 22

All levels of the IV are administered sequentially to all subjects

Disadvantages:

• carryover effects
• pre/post test autocorrelation confound

Question 23

Mixed Designs

Answer 23

Combines between-groups and within-subject designs

Requires at least one between-groups IV and
one-within subjects IV

Question 24

Single-Subject Design

Answer 24

Includes at least one baseline phase and one treatment phase

Subject acts as their own no-treatment control

DV is measured repeatedly at regular intervals throughout baseline and treatment phases

Question 25

Single-Subject: AB Design

Answer 25

Single baseline phase (A)

Single treatment phase (B)

*multiple dv measurements in each phase

Question 26

Single-Subject: Reversal Designs (ABA, ABAB…)

Answer 26

Withdrawal of treatment during second and subsequent baseline phases

Advantage: controls for history, maturation and other threats to internal validity

Question 27

Single-Subject: Multiple Baseline Design

Answer 27

Used when reversal design is is inappropriate for ethical or practical reasons (e.g withdrawing useful tx)

IV sequentially applied to the same subject to create multiple baselines (IV is never withdrawn)

E.g. sequentially measuring different behaviors/ settings / tasks

Question 28

Interrupted Time Series Design

Answer 28

One Group

DV measured at regular intervals before and after tx

dv NOT measured during tx

Question 29

Single-Subject Reversal Designs (ABA, ABAB…):

DV baseline levels

Answer 29

DV returns to original baseline level following a treatment phase

= Evidence that IV is having a true effect

Question 30

Solomon four-group design

Answer 30

Evaluates effects of pretest on internal and external validity

Treats pretest as IV