"Differential Item Functioning, Second Edition" is a revision of the 1983 title Test Item Bias. In the past 23 years, differential item performance has assumed a level of attention unimagined in the early 1980s. Then, only a few tests and assessment programs attended to 'item bias,' while doing so is now a mandatory step in any responsible assessment program. Also, technical advances, such as the widespread use of item response theory, have pushed the field of differential performance to levels of technical sophistication far beyond what was practiced years ago. This new edition presents an up-to-date description of DIF; describes varying procedures for addressing DIF in practical testing contexts; presents useful examples and studies of DIF that readers may employ as a guide in their own DIF work; and briefly describes relevant features of major statistical packages that can be employed in DIF analysis (e.g., SPSS, SAS, M+, Minitab, and Systat). This text is ideal for the measurement professional or advanced student who deals with educational or psychological assessment. Readers need only have a preliminary background in tests and measurement, including some beginning statistics and elementary algebra, in order to find this volume useful.