An empirical study on the effect of arrangement on performance of two inspectors

The manufacture of critical applications often requires a low or zero defect level. To ensure quality is not compromised when high product reliability is required, quality-engineering departments frequently employ 100% inspection. Given the fallibility of human inspectors though, re-inspection procedures, at times, may have to be implemented. This paper analyzes various multi-inspector scenarios to determine what arrangement produces the highest quality output. Focusing on the use of two inspectors, it emphasizes the use of existing inspection processes and the modifications that will improve inspection performance without increasing inspection time or cost. The results from different arrangements of inspection teams were then analyzed to determine how well theoretical models predict real-world performance. Although various models have been developed in the past to predict multi-person inspection scenarios, they were based on inspection theories, not empirical data, as was the case in this study.