EXPERIMENTAL RESEARCH DESIGNS
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Examples in business, educational, medical, and sports (steroids, slugging percentage, Ballpark),
research
Reading
Four components of a research design
o Comparison
 Cross-sectional
 Longitudinal
 Concomitant variation
o Manipulation
 Ex post facto
 Real world
o Internal validity—prove what it claims? Other factors (confounding variables)? Rival
explanations?
 Intrinsic factors—control group
 History
 Maturation
 Pre-test bias
 Extrinsic factors—similarity of groups
 Randomization
 Matching
o External validity
True Experimental Designs
o “True experiment”
o “Four group design”
Pre-experimental designs
o One-shot case study
o One-group pretest-post
Quasi-experimental designs
o “Natural experiment”
o True experiment with matching
Examples
o Agency study
o Spock revolution
o Organizing the poor
o Tax reform
o Presidential lobbying