• Research validity - internal, external

• Threats to validity, especially:

  • selection

  • statistical regression

  • history

  • mortality

  • maturation

• Different research designs, especially:

  • pretest-postest, control group design

  • postest-only control group design

  • nonequivalent comparison group design

  • time series design

Other Specific Points:

• Relationship between internal validity and external validity
• Purpose of randomizantion in research design
• Astin one-page article, "College Retention Rates are Often Misleading", understand the research design issues
• Regression towards the mean effect - understand which direction it will bias results
• How to assess the seriousness of the selection threat in the nonequivalent control group design
• Be able to diagram the common research designs
• Random assignment of matched pairs