The growth in the availability of longitudinal data--data collected over time on the same individuals--as part of program evaluations has opened up exciting possibilities for evaluators to ask more nuanced questions about how individuals' outcomes change over time. However, in order to leverage longitudinal data to glean these important insights,…

Discusses how to examine and evaluate claims of improved academic performance in advertisements for computer-assisted instruction. Highlights include the proper use of comparison groups; types of statistical analyses; the Hawthorne effect; the interpretation of scores; interpreting graphic presentations; tests of significance; and cost…