Non-experimental Design

Non-Experimental Design (AKA pre-experimental design)

One group Posttest (AKA one shot case study)

​​​​​One-group pretest-posttest

​​​Static comparison/posttest only design with nonequivalent groups

​No comparison group or pre-test scores. Impossible to determine if the outcome scores are any higher than they would have been without the treatment or​​​​​​ determine if any change within the group itself has taken place.

Subjects are presented with some type of treatment. After treatment, an outcome measure (post-test) is applied.

Determine if the treatment had any effect on the outcome

Procedure

Goal

Problems

Procedure

Pretest administered to determine baseline. Subjects are presented with some type of treatment. After treatment, posttest administered to determine change.

Goal

determine if the treatment had any effect on the outcome

Because of pretest baseline can now at least state whether a change in the outcome (dependent variable) has taken place.

Advantages

If change occurs, cannot say if this change would have occurred even without the application of the treatment (independent variable).

Problems

Procedure

​​​Two groups are chosen. One receives treatment and the other does not. After treatment, posttest administered to determine change between the two groups.

Goal

determine if the treatment had any effect on the outcome.

Advantages

Does include control group

Does not include pretest. Any difference between the two groups prior to the study are unknown so don’t really know what effect treatment has.

Problems