PPT Slide

COMPARISON OF RANDOM GROUPS (RG) DESIGN VS. ONE-GROUP,

PRETEST-POSTTEST (OGPP) AND STATIC GROUPS COMPARISON

(SGC) DESIGNS IN TERMS OF APPLICABILITY OF CAMPBELL AND

STANLEY’S SIX ADDITIONAL THREATS TO INTERNAL VALIDITY

RG OGPP SCG

SELECTION X HISTORY No No Yes

SELECTION X MATURATION No No Yes

SELECTION X INSTRUMENTATION No No Yes

CONTAMINATION No No Yes

HAWTHORNE EFFECT No Yes Yes

EXPERIMENTER EXPECTATION No No No

Note : “Yes” means the threat is unavoidable