Below are some common research designs. Each has strengths and weaknesses. The rows within each design represent different groups. The columns represent the passage of time.

R=Random Assignment
X= Treatment
O=Observation (Assessment)

		X	O	One Shot Case Study Design
	O	X	O	One-Group Pretest-Posttest Design
		X	O	Static-Group Comparison Design
			O
	O	X	O	Static-Group Pretest-Posttest Design
	O		O
R		X	O	Randomized Posttest-Only, Control Group Design
R			O
R	O	X	O	Randomized Pretest-Posttest Control Group Design
R	O		O
R	O	X	O	Ranomized Solomon Four-Group Design
R	O		O
R		X	O
R			O

R = Random Assignment
X = Treatment
O = Observation (test or measurement of some type)

Del Siegle, Ph.D.
Neag School of Education – University of Connecticut
del.siegle@uconn.edu
www.delsiegle.com