Quasi-experimental designs were developed to deal with the messy world of field research, where it is not always practical, ethical, or even possible to randomly assign persons to experimental and control groups.

The little orange ball beside each design is "clickable" and will take you to a discussion of that design.

Some examples of quasi-experimental designs are:

Time Series Design

Control Group Time Series Design

Equivalent Time Samples Design

Equivalent Materials Design

Non-equivalent Control Group Design

Counterbalanced Designs

Separate Sample Pretest-Posttest Design

Separate Sample Pretest-Posttest Control Group Design

Multiple Time Series Design

Recurrent Institutional Cycle Design