Investigating the Sources and Causes of Schedule Instability

The sources and consequences of schedule instability at an automotive assembler producing two models on the same assembly track are described. One model was produced under conditions of relatively lengthy stable schedules, the other under more unstable schedule conditions. The two logistics processes were compared, and measures of schedule uncertainty identified. The relative impact on human resources was explored by investigating constructs of the two production systems according to people who worked in the processes. Relative quality and productivity of the two systems were evaluated. It was concluded that there were advantages in both of these measures for the more stable production system, and that the supply chain and core manufacturing process were relatively lean. But the less stable production system provided greater responsiveness to the market and greater discretion to people working in the process.