The answer to the question, "Ability, speed, or both?" may be "both at once" if speed is simply a manifestation of ability. If differences in speed are manifestations of differences in ability, then both speed and ability may reflect a single dimension best characterized by a single score. While measurement of speed has proven…

In this commentary, Kuhn and Ranger hypothesize that most people are aware that talent does not guarantee success in case one is lazy. This is also true for the performance in achievement tests that depends on, among other factors, achievement potential (ability) and willingness to achieve (test-taking motivation) of the test taker. They add that…

The excellent paper by Goldhammer (this issue) deals with a most relevant and very pervasive problem of ability assessment: the evaluation of performance by considering speed and accuracy of performance. Goldhammer proposes item-level time limits as a possible remedy for individual differences in the speed-accuracy trade-off (SATO) to keep time…

The growing presence of computer-based testing has brought with it the capability to routinely capture the time that test takers spend on individual test items. This, in turn, has led to an increased interest in potential applications of response time in measuring intellectual ability and achievement. Goldhammer (this issue) provides a very useful…

The main challenge of ability tests relates to the difficulty of items, whereas speed tests demand that test takers complete very easy items quickly. This article proposes a conceptual framework to represent how performance depends on both between-person differences in speed and ability and the speed-ability compromise within persons. Related…

This article is a commentary of a paper by Derek C. Briggs and Frederick A. Peck, "Using Learning Progressions to Design Vertical Scales That Support Coherent Inferences about Student Growth," which describes an elegant potential framework for at least beginning to address three priorities in large-scale assessment that have not been…