Study Design

Looking at a studies design helps to determine internal validity and causality of said study. It explains simply what you did and to whom you did it.The design of the study looks at the number of groups and measurements, the independent and dependent variables, and whether the sample was randomly assigned.

The researcher can enhance internal validity by having a comparison group and a control group. Furthermore, randomly selecting and assigning participants can increase internal validity and reduce selection bias.

Three Types of Design

1. Pre-experimental
   • Pilot study
   • Usually one group (makes this type vulnerable to threats to internal validity)
   • Exploratory
2. Quasi-experimental
   • Does not involve random assignment
   • Usually two groups
   • Descriptive
3. Experimental
   • Cause and effect
   • Groups, random assignments,… etc
   • Explanatory

Design outcomes is based on the…

• Number of groups
• Number of measures
• Random or not