S-PI: A performance measurement system using an S-curve

This method is a tool for evaluating the performance of any production system. It is based on the work of (1), with an evaluation structure consisting of a three-level hierarchy. Evaluation groups are at the top level, below which groups of metrics or key performance indicators (KPIs) are located; performance indicators (PIs) are located below the KPIs. To consolidate several types of metrics, in a single evaluation, it is necessary to normalize the values. This study overcomes the deficiencies of the original method, which linearly normalizes the PIs between 0 and 1. For an indicator with a goal of 100%, a compliance of 70% would be evaluated as 70% of the desired value. In reality, the decision maker may consider 70% to be equivalent to 30% of the desired value. To more realistically simulate the evaluator's preference scale, an S-shaped curve based on the Weibull distribution is adopted. This curve must be calibrated to reflect the preferences of the evaluator. This study shows all the steps of structuring an evaluation system, with details for the calibration of the S-curve parameters. • Evaluation scales are not linear. • The S-curve better reflects stakeholder preferences.