Aspects of Reseach Design

1. Extent of Researcher’s Ability to Control

True-Experimental Design

participants can be randomly assigned to groups

IV can be manipulated

Quasi-Experimental Design

participants are in preexisting groups

so random assignment is impossible

e.g., gender; age

IV can be manipulated

Correlational Design (Pre-Experimental Design)

IV cannot be manipulated

2. Nature of Comparison

Between-Subjects Design

different groups of participants get different values of IV

comparison among groups

Within-Subjects Designs

same participants get different values of IV

comparison over time

3. Number of Ivs and DVs; Levels of IV

Factorial Experimental Designs

several IVs

random assignment

each group receives a combination of IVs

permits assessment of "interactions"

Multivariate Designs

several DVs

Multiple Correlation Research

preexisting groups

nonexperimental design for multiple Ivs

4. Additional Designs we will explore in a later class...

Single-Subject Designs

Developmental Designs

Longitudinal Designs

Cross-Sectional Designs

Cross-Sequential Designs