TOPICS APPROPRIATE TO EXPERIMENTS

Enhancement Module: Internal Invalidity Enhancement Module: Experimental Design

THE CLASSICAL EXPERIMENT
    Independent and Dependent Variables
    Pretesting and Posttesting
    Experimental and Control Groups
    The Double-Blind Experiment
SELECTING SUBJECTS
    Probability Sampling
    Randomization
    Matching
    Matching or Randomization?
VARIATIONS ON EXPERIMENTAL DESIGN
    Preexperimental Research Designs
    Validity Issues in Experimental Research
AN ILLUSTRATION OF EXPERIMENTATION
"NATURAL" EXPERIMENTS
STRENGTHS AND WEAKNESSES OF THE EXPERIMENTAL METHOD