Abuses and misuses of statistics are frequent. This digest attempts to warn against these in three broad classes of pitfalls: sources of bias, errors of methodology, and misinterpretation of results. Sources of bias are conditions or circumstances that affect the external validity of statistical results. In order for a researcher to make…

Too few researchers understand what statistical significance testing does and does not do, and consequently their results are misinterpreted. This Digest explains the concept of statistical significance testing and discusses the meaning of probabilities, the concept of statistical significance, arguments against significance testing,…

This digest reviews scientific and methodological problems in special education research related to race, ethnicity, and socioeconomic status. The first section of the digest discusses the various definitions of race, ethnicity, culture, and socioeconomic status. The problems with current race classification and the difficulties in determining the…