Reliability of Process‐Time Prediction for Semi‐Repetitive Processes

Abstract This is the fourth of a four‐part series on “Engineering Implications of Semi‐repetitive Processes” ( see Part 1, Engineering Implications of Semi‐Repetitive Processes , Part 2, The Dual‐Component Variation of Semi‐Repetitive Processes , and Part 3, Measuring Repetitiveness of Semi‐Repetitive Processes ). In Part 3, we have examined and compared several candidate measures to evaluate process repetitiveness, the basis for evaluating predictability of a semi‐repetitive process. In particular, we have evaluated the coefficient of variation (CV) and found it to be statistically linearly related to process repetitiveness measure (PRM), which measures process repetitiveness based on the standardized distance of the mode from the mean (find details in stat08661). In this entry, we employ CV to address how process degree of repetitiveness affects its predictability. More specifically, we formulate for semi‐repetitive processes a statistical criterion by which to determine when process‐time predictions cease to be acceptable due to insufficient process repetitiveness.