Performance improvement analysis of a supermarket checkstand: A computer simulation approach

Purpose: The purpose of this paper is to describe the use of computer simulation for performance improvement analysis for a large-scale ergonomic intervention and redesign project of a supermarket checkstand. Owing to its relatively complex operating logic, coupled with myriad physical characteristics of grocery items and variable buying patterns, conventional methods of analysis are impractical. Design/methodology/approach: The probability distributions of activity time elements and system characteristics are determined from video analysis of the checkstand operation. A SLAM II model represented the functional logic and random samplings from probability distributions simulated effects of variable grocery characteristics and buying patterns. The utilization indices obtained from the model facilitated prioritizing design improvements. The proposed design changes of the checkstand are implemented in the model by applying scaling factors estimated from the predetermined time standards. Findings: The mean performance rates of the present and the proposed (ergonomic) checkstand design are predicted within ±2 percent of the true mean values with 90 percent confidence. Owing to high variability of activity time elements and system parameters, it would be impractical or would be prohibitively expensive to achieve comparable precision level of analysis, if a conventional time study technique is used. Originality/value: This investigation has demonstrated for the first time that a computer simulation methodology can be used advantageously for determining the effect of design layout change of a complex workstation, such as a supermarket grocery checkstand.