Group and design types

Question 1

Case-control designs

Answer 1

Study characteristics of interest by forming groups of individuals who vary on that characteristic. Basic-two group version (cases=subjects who show characteristic, controls=subjects who do not show the characteristic). The IV is the characteristic that served as the basis for the group “assignment.” Groups are compared on measures of interest (DVs). Two major variations of this design based on the “time perspective” (i.e., current or past).

Question 2

Cohort designs

Answer 2

The study of intact groups over time; AKA prospective longitudinal study. Follow samples over time to identify factors leading to specific outcome. Group is assessed before outcome has occurred (compared to case-control designs where outcome has already occurred (i.e., in the cases but not controls). Strength of design is in being able to establish a time line of events and that the cause has preceded the effect. (types are single group cohort design and multi-group cohort design).

Question 3

Retrospective study

Answer 3

The goal is to draw inferences about some antecedents that has resulted in or is associated with the outcome. The outcome of interest allows groups to be formed (cases vs controls). Attempt to identify a timeline between cause and effect. Measures are designed to allow subjects to elaborate on the past (susceptible to memory and recall effects). Thus, effect preceding the cause in time is plausible. However, may not be able to rule out alternative explanations for the outcome of interest.

Question 4

Cross-sectional case-control designs

Answer 4

Most common version used in psychology (describe and explore characteristics of interest, test theoretical or conceptual models). Cases and controls selected and assessed in relation to current characteristics (not based on past experiences [retrospective]). Hypotheses are established about how groups will differ. Results are correlational-difficult to determine if outcome preceded OR was caused by a characteristic.

Question 5

Retrospective case-control designs

Answer 5

The goal is to draw inferences about some antecedent that has resulted in or is associated with the outcome. The outcome of interest allows groups to be formed (cases vs control). attempt to identify a timeline between cause and effect. Measures are designed to allow subjects to elaborate on the past (susceptible to memory and recall effects). Thus, effect preceding the cause in time is plausible. However, may not be able to rule out alternative explanations for the outcome of interest.

Question 6

Two central characteristics of observational research design:

Answer 6

• Study of intact groups (i.e., no random assignment)

- Examination of variables that cannot be manipulated experimentally

Question 7

Key features of an accelerated multicohort longitudinal design

Answer 7

Inclusion of cohorts who vary in age when they enter the study (less time than if one group was studied over a specific time period)

Question 8

Between-group design

Answer 8

Design where subjects are only assigned to one group and only receive one treatment. If you are in one group, you cannot be in the other.

Question 9

Within-subject design

Answer 9

(Same as repeated-measure design [confirmed by Dr. M])Design where all subjects receive the same treatment.

Question 10

Repeated measures design

Answer 10

(Same as within-subject design [confirmed by Dr. M]) Where you use the same subjects for every branch of research. An example of this would be a longitudinal study.

Question 11

What are the categories of design within observational design?

Answer 11

• Case control (therein, cross sectional and retrospective)

- Cohort (therein, prospective/longitudinal)

Question 12

Quasi-experimental design

Answer 12

Study control groups are still used, but subjects are not randomly assigned to conditions. [Characteristics of the population or sample do not permit random assignment. Thus the plausibility of threats to validity may not be reduced. Since groups have already been formed they are also referred to as nonequivalent control group designs] this type of study has to control for confounding variables by selecting appropriate controls or through statistical techniques.

Question 13

Multiple treatment design

Answer 13

Some research questions require that all subjects perform under all of the experimental conditions available. In multiple treatment designs the same participants perform in all of the conditions of a give experiment. Then subject scores are compared in the aggregate within the various conditions to determine the extent of a give effect. While the evaluation of treatment is “within-subjects” separate groups are usually used so that the different treatments may be balanced. Different versions differ based on the number of treatments and they way in which they are presented.

Question 14

Solomon four

Answer 14

• Purpose of this design is to assess the effect of pretesting on the effects obtained with an intervention. Two groups as reflected in a pretest-postest control group design. And two groups as reflected in a postests-only control group design.

Question 15

Factorial designs

Answer 15

Simultaneous investigation of two or more factors (IV). Each factor or IV must have at least two or more groups/conditions/levels.Multiple variables are included to address questions about separate (main effects) and combined (interaction) effects of different variables.

Question 16

Multiple–baseline design

Answer 16

Utilizes baseline and intervention. Demonstrates intervention effect by showing behavior change at different points in time when intervention is introduced. Data collected continuously and concurrently. Evaluation of change across different baselines. The baseline condition is extended for increasing lengths of time as the intervention is introduced with other DVs. Intervention introduced a second time once data stabilizes.

Question 17

Changing criterion design

Answer 17

Demonstrates behavior change in increments. When intervention is introduced,a specific level is chosen as criteria for performance. When performance meets or surpasses the criterion level, a consequence is provided. Then the criterion level is changed and the subject must meet the new level consistently. This process is repeated until the end goal of the program is achieved.

Question 18

A-B Design

Answer 18

• DV is measured at baseline (A) and then again during the intervention phase (B)
• The effect of the IV is demonstrated once
• This design does not provide adequate protection against various threats to internal validity.

Question 19

A-B-A Design (withdrawal designs)

Answer 19

• Includes a phase that involves a return to the original baseline condition
• If the DV returns to a pattern that is similar to the original baseline, then one can make stronger assumptions about the casual role of the IV
• The return to baseline patterns is inferred to be due to the withdrawal of the IV

Question 20

A-B-A-B Design (withdrawal designs)

Answer 20

• AKA equivalent time-samples design, the withdrawal design, the reversal design.
• Design allows for two opportunities to compare the behavior patterns during baseline and treatment conditions.
• A compared to B, and B compared to A

Question 21

Single-subject withdrawal designs (ARE YOU SICK OF THIS YET??)

Answer 21

o	The B-A-B Design
o	Variations of the A-B-A design
o	A-B-A-C-A-C
o	A-B-A-C-A-C
o	Introduces a condition in which the effects of a second IV are examined