This special issue of "Assessment in Education" contains the type of debate needed about what Cizek (2015) calls a "… lingering flaw in the concept of validity…." Some practitioners might not agree that the current theory of validation is flawed. Specifically, the debate Jon Twing is referencing concerns the role of the…

Some theoretical background is presented for the proposition that thinking processes can be measured by determining the levels of cognitive complexity apparent in written interpretations of complex situations. The rationale for scoring interpretations is presented, and some illustrative data are discussed. The approach to measurement of thinking…

A new approach to the quantification and interpretation of change when only repeated cross-sectional data are available--the Trajectory Analysis of Matched Percentiles--is presented. A recent attempt to interpret the findings on reading achievement of the National Assessment of Educational Progress is critically analyzed. (SLD)