Research design: Pretestposttest control group

1
Research designPretest-posttest control group
R O X O R O O
Weakness Interaction of pretest and X
2
Research designPosttest-only control group
R X O R O
No general weaknesses Sometimes not feasible
3
Research design One-group pretest-posttest
O X O
Weaknesses History Maturation
Testing Instrumentation Interaction
between testing and intervention
4
Research designOne-shot case study
X O
Weaknesses History Selection/mortality
Generally not scientific
5
Data analysis
Descriptive statistics Central tendency mean,
median, mode Dispersion variance, standard
deviation, range Other types of analyses that
are common Differences between means t test, F
test Relationships cross-tabulation (chi
square), correlation
6
New usability problems identified by each
successive study participant(Spool Schroeder,
2001)