Overview of Study Designs1 NOTE: Pretest is used to define any pre-measurement observation of the group. This could be an attitudes questionnaire, a knowledge-based exam, etc. Posttest is defined the outcome variable being measured.

Experimental Designs Pretest-Posttest Control Group Design Group Time Random Group 1 Pretest Intervention Posttest Assignment Group 2 Pretest Posttest

Solomon Four-Group Design Group Time Group 1 Pretest Intervention Posttest Random Group 2 Pretest Posttest Assignment Group 3 Intervention Posttest Group 4 Posttest

Posttest Only Control Group Design Group Time Random Group 1 Intervention Posttest Assignment Group 2 Posttest

Within-Subjects Design Group Time Random Group 1 Intervention 1 Posttest 1 Assignment Group 2 Intervention 2 Posttest 2

Quasi-Experimental Designs Nonrandomized Control Group Pretest-Posttest Design Group Time Group 1 Pretest Intervention Posttest Group 2 Pretest Posttest

Simple Time Series Experiment Group Time Group 1 Pretest Pretest Intervention Posttest Posttest

Control Group Time Series Experiment Group Time Group 1 Pretest Pretest Intervention Posttest Posttest Group 2 Pretest Pretest Posttest Posttest

Simple Ex Post Facto Design (Causal Comparative Design) Group Time Group 1 Intervention Posttest Group 2 Posttest

Pre-Experimental Designs Cross-Sectional Study Design Group Time Group 1 Intervention Posttest

Single Subject/Case Study Design Group Time Group 1 Pretest Intervention Posttest

Cohort Study Design/Static Group Comparison Group Time Group 1 Intervention Posttest Group 2 Posttest

Factorial Designs Randomized 2-Factor Design Group Time Group 1 Intervention 1 Intervention 2 Posttest Random Group 2 Intervention 1 Posttest Assignment Group 3 Intervention 2 Posttest Group 4 Posttest

Combined Experimental and Ex Post Facto Design Group Time Group 1 Experience 1 Random Group 1a Treatment 1 Posttest Assignment Group 1b Treatment 2 Posttest Group 2 Experience 2 Random Group 2a Treatment 1 Posttest Assignment Group 2b Treatment 2 Posttest

1. Leedy PD, Ormrod JE. Practical Research: Planning and Design (8th Ed.). Upper Saddle River, NJ: Merrill Prentice-Hall, 2005.