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Between-Groups Experimental Design and Validity
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Between-Groups Experimental Design and Validity
Chapter 7 Flashcards
Study
1
Question
What is the primary purpose of a between-groups research design?
Answer
Between-groups designs examine how an intervention differs across groups or describe how separate groups vary across a specific construct.
2
Question
How does a univariate analysis of variance differ from a multivariate analysis of variance?
Answer
An analysis of variance examines one or more independent variables on a single dependent variable. A multivariate analysis of variance includes two or more dependent variables.
3
Question
Why is dummy coding executed with values of 0 and 1 rather than 1 and 2 in regression?
Answer
Using 0 and 1 treats 0 as the baseline constant and 1 as the predictor variable. Using 1 and 2 would mathematically weight the second group higher, corrupting the analysis.
4
Question
How is construct irrelevance defined in educational and psychological measurement?
Answer
Construct irrelevance is the degree to which test scores are affected by processes extraneous to the test's intended purpose.
5
Question
What distinguishes a true experimental design from a quasi-experimental design?
Answer
True experimental designs utilize both a manipulated independent variable and random assignment. Quasi-experimental designs feature a manipulated independent variable without random assignment.
6
Question
What defines an explanatory nonexperimental research design?
Answer
Explanatory nonexperimental designs compare existing groups on a construct without manipulating an independent variable or using random assignment.
7
Question
How do independent variables and dependent variables fundamentally differ in between-groups analyses?
Answer
The independent variable is a discrete categorical variable defining study groups. The dependent variable is typically a continuous variable representing the measured outcome.
8
Question
How do levels within a single independent variable differ from multiple independent variables?
Answer
Levels represent the specific conditions or subgroups within one independent variable. Multiple independent variables refer to completely separate grouping factors in a factorial design.
9
Question
In what situation can a dependent variable be discrete rather than continuous?
Answer
A dependent variable is discrete when the measured outcome consists of categorical classifications, such as distinct time-to-reoffense categories or binary relapse status.
10
Question
What is the core distinction between internal experimental validity and external experimental validity?
Answer
Internal validity addresses whether changes in the dependent variable resulted directly from the independent variable. External validity refers to the generalizability of findings to real-world settings and populations.
11
Question
How does the internal validity threat of maturation affect study outcomes?
Answer
Maturation occurs when natural developmental, emotional, physiological changes, or fatigue over time alter participant performance independently of the intervention.
12
Question
What characterizes the history threat to internal experimental validity?
Answer
History refers to external events occurring outside the study that differentially influence participants in one group but not another.
13
Question
Why does repeated administration of a test pose a testing effect threat to validity?
Answer
Repeated administration allows participants to become overexposed or familiar with the instrument, which can artificially alter their subsequent responses.
14
Question
What constitutes an instrumentation threat to internal experimental validity?
Answer
Instrumentation threats occur when an administered measure lacks evidence for valid use, becomes inconsistent, or produces inaccurate scores across administrations.
15
Question
How do baseline effects and ceiling effects manifest in statistical regression?
Answer
Baseline effects occur when initial scores are at the lowest end and can only improve. Ceiling effects occur when initial scores are at the highest end and cannot increase further.
16
Question
Under what conditions does selection bias threaten internal validity?
Answer
Selection bias occurs when study groups are fundamentally unequal or differ vastly on participant characteristics at the outset of the study.
17
Question
How does participant mortality threaten the validity of counseling research?
Answer
Mortality, or participant attrition, results in incomplete or missing data, which threatens whether the remaining sample accurately represents the population of interest.
18
Question
What mechanism explains how experimenter bias undermines study findings?
Answer
Experimenter bias happens when the researcher's expectations predispose participants toward specific responses, particularly when the researcher administers interventions and evaluates data.
19
Question
What is the primary scientific advantage of utilizing random assignment in experimental research?
Answer
Random assignment disperses extraneous participant characteristics equally across groups, preventing those variables from confounding the study results.
20
Question
How can researchers achieve statistical control when random assignment cannot be performed?
Answer
Researchers can either use regression procedures to statistically adjust dependent variable scores across continuous covariates, or match participants across demographic characteristics.
21
Question
Why does the artificiality of a clinical setting compromise external validity?
Answer
Rigid, highly structured settings like inpatient hospitals do not mirror real-world pressures, making client coping skills difficult to replicate in natural environments.
22
Question
How does interference of prior treatment affect the external validity of an intervention?
Answer
Participants with extensive treatment histories may respond differently than treatment-naive individuals, preventing findings from generalizing to broader populations.
23
Question
What occurs during an interaction of selection and treatment?
Answer
An interaction of selection and treatment occurs when findings are restricted to the unique characteristics of volunteer or intact groups rather than the broader population.
24
Question
How does an interaction between testing and treatment threaten external validity?
Answer
A pretest may sensitize or alter the groups differently, meaning the intervention's observed success only occurs in the presence of that specific pretest.
25
Question
Why is treatment fidelity critical for preventing an interaction of treatment implementation?
Answer
Treatment fidelity ensures that interventions are delivered consistently across participants and trials; without it, variations in delivery prevent generalizable conclusions.
26
Question
What are the three essential components of a true experimental design?
Answer
A true experimental design requires random assignment, a manipulated independent variable, and a measure of effect or change.
27
Question
What is the structural sequence of a posttest-only control group design?
Answer
The treatment group receives the intervention followed by an outcome measure. The control group receives no intervention (or an alternative) followed by the same outcome measure.
28
Question
What is the primary methodological risk of using a posttest-only design without random assignment?
Answer
Without random assignment or statistical matching, researchers cannot verify group equivalence at baseline, creating severe threats to internal validity.
29
Question
What is the operational structure of a pretest-posttest control group design?
Answer
Both groups take a pretest, after which the treatment group receives the intervention while the control does not, culminating in a posttest for both groups.
30
Question
What dual purpose does a pretest serve in an experimental study?
Answer
A pretest verifies initial group equivalence prior to the intervention and provides a baseline to demonstrate changes across time.