This chapter is about measuring task performance in personnel selection research. When evaluating the validity of selection tests and procedures, the accuracy of these validity estimates depends in turn on the accuracy of criterion performance measurement. Initially, sales jobs may seem ideally suited for the use of objective criteria as performance measures. Longer periods for data collection may be necessary to ensure stable criterion production rates. One issue in work sample scoring is whether to evaluate products or process relative to work sample performance. Dimensions identified by Chockalingam Viswesvaran included interpersonal competence, administrative competence, quality, productivity, effort, job knowledge, leadership, compliance/acceptance of authority, communications competence, and an overall job performance dimension. Rater training provides a promising approach to improving the quality of performance ratings. Mike Smith and Kendall extended the notion of critical incidents by designing a rating format they referred to as behavioral expectation scales, now generally labeled behaviorally anchored rating scales.