Mapping workers’ performance to analyse workers heterogeneity under different workflow policies

• From industrial data the performance heterogeneity of assembly line operators is assessed.
• A mapping approach is proposed to assess variations in terms of speed and variability.
• Two scenarios were studied concerning the influence of work flow policies on human performance.
• The heterogeneity of workers performance was characterized into different classes.

Manual work in assembly lines allows one to benefit from human reasoning capabilities and to assure the flexibility to adapt to fluctuations in production volume, products mix and reduced product lifecycles. With the objective of quantifying and systematizing the knowledge about the heterogeneity of workers’ performance, data was collected in an industrial setting. The results demonstrate a significant variation in workers’ performance in terms of speed and variability of the task completion time. A mapping approach is proposed aiming to quantify the workers’ performance and visualize performance patterns. Since the human performance is influenced by the setting where the workers perform their job, two real assembly line pacing mechanisms were set and studied: pacing derived from the manual assembly system rhythm and pacing imposed by a fixed time constraint. The type of pacing clearly influences workers’ performance (i.e., speed and variability) and revealed a significant influence in the assembly line output. In particular, imposing a fixed and equal time constraint for every worker reduces the heterogeneity of workers’ performance and improves the assembly line output.