This "What Works Clearinghouse Procedures and Standards Handbook (Version 3.0)" provides a detailed description of the standards and procedures of the What Works Clearinghouse (WWC). The remaining chapters of this Handbook are organized to take the reader through the basic steps that the WWC uses to develop a review protocol, identify…

This repeated measures factorial design study compared the results of two procedures for identifying multivariate outliers under varying conditions, the Mahalanobis distance and the Andrews-Pregibon statistic. Results were analyzed for the total number of outliers identified and number of false outliers identified. Simulated data were limited to…

Although it is widely known that special assumptions are needed for univariate analysis of repeated measures data, researchers seldom examine their data for violation of these assumptions. This paper reviews ways in which repeated measures analyses are usually handled and describes limitations of these methods. A design with two within subject…

This paper comments on the impact of computers on statistical analysis and presents a concise, nontechnical overview of five statistical methods now being applied in educational research. Appropriate uses of these techniques are pointed out, along with dangers concerning misapplications. (PP)

Many times in both educational and social science research it is impossible to collect data that is complete. When administering a survey, for example, people may answer some questions and not others. This missing data causes a problem for researchers using structural equation modeling (SEM) techniques for data analyses. Because SEM and…

Hypothetical data sets are used to demonstrate how canonical correlation methods subsume other commonly utilized parametric methods. Analysis of variance, analysis of covariance, multiple analysis of variance, and multiple analysis of covariance are heavily used by educational researchers. It is concluded that researchers would do well to consider…

The conclusion of a 1999 Organisation for Economic Cooperation and Development (OECD) report that wage gains for training are higher for workers with lower levels of education was revisited using data for males from the 1997 Australian Survey of Education and Training (SET). The study used methods similar to the OECD report (ordinary least squares…

One limitation of hired farm labor data from the Decennial Census is undercounting; the seasonal nature of farm work means that many farm laborers are not employed in March, when the Census is taken. The 1981 Hired Farm Working Force Survey provided data to evaluate the usefulness of Census data for farm labor research. Data were grouped into…