A comparative study of performance measures for throughput of a mixed model assembly line in a JIT environment.

Throughput evaluation of a mixed model assembly line, where the arrival sequence of items is randomly distributed, is a very difficult task, and the use of performance measures is required. An essential condition for using a performance measure is its validity. In this paper, a six-stage validity study of five alternative performance measures is carried out. The study is based on a comparison between calculated performance measures for throughput with simulation results, using the Spearman correlation coefficient. A full experimental study is developed, evaluating the validity of each measure in a wide range of problem environments. Results indicate that the performance measure based on the probability of a station becoming a bottleneck is highly correlated with simulation results, and was found to be the best measure in almost all experiments.