SECTION V

CHAPTER 14

GROUP COMPARISON RESEARCH

Types of Group Comparisons

Independent and Dependent Variables

    Confounding Variables

Ex Post Facto (or Causal Comparative) Designs

    Ex Post Facto Designs and Causality

 

Internal and External Validity of Experiments and Quasi-Experiments

Threats to Internal Validity

    INTERNAL VALIDITY

        HISTORY

        MATURATION

        PRE-TESTING

        MEASURING INSTRUMENTS

        STATISTICAL REGRESSIN

        DIFFERENTIAL SELECTION OF SUBJECTS

        EXPERIMENTAL MORTALITY

        SELECTION-MATURATION INTERACTION

    2. EXTERNAL VALIDITY

        POPULATION VALIDITY

        ECOLOGICCAL VALIDITY

    Pre-Experimental Designs

    True Experimental Designs

    Quasi-Experimental Designs

 

Experiments

    The Function of Random Assignment

    Random Assignment and Causality

    Problems with Random Assignment

Random Assignment and Sample Size

    Assignment by Matched Pairs

 

Quasi-Experiments

    Random Assignment of Intact Groups

Problems Associated with Pre-tests

    Measuring Changes in Attitudes

The Hawthorne Effect

The John Henry Effect

    Controlling for the Hawthorne and John Henry Effects