In Great Britain, interest in the measurement of value added was stimulated initially by the requirement that schools and further education (FE) colleges publish league tables of examination results. Value-added data can be aggregated to compare different institutions' performance. Within colleges, value-added data provide a basis for setting targets, monitoring performance, and identifying patterns of success and failure. Measuring value added entails comparing the characteristics and attainments of learners at entry (input data) and their achievements at exit (output data). Where correlation between input scores and output scores is high, value-added data can also be used to motivate and improve the performance of individual students by setting realistic targets and monitoring progress. According to a recent study that measured the performance of nearly 2,000 students in General National Vocational Qualifications (GNVQ) advanced programs at 10 FE colleges, nationwide application of a uniform methodology for the measurement of value added on vocational courses is not presently feasible. The General Certificate of Secondary Education is the best predictor of GNVQ attainment. Colleges should not, however, be discouraged from using local value-added measurements, provided those measurements are based on a sound statistical methodology. (15 references) (MN)