Absenteeism as a major cause of bottlenecks in serial production processes

This paper shows that absenteeism in assembly lines and production lines is a major cause of bottlenecks. A bottleneck typically appears as an inexperienced worker replaces an absentee worker at his position. The inexperienced worker starts his/her learning curve, and for a certain period is slower than other stations, and therefore is a bottleneck. The paper analyzes the effect of typical absenteeism rates on the throughput, and shows it has strategic magnitude. This is verified using simulation. The effect of the absenteeism and turnover on the throughput is found to be related to the cycle time, and the amount and rate of learning. The paper compares two popular strategies for overcoming absenteeism and turnover: (a) assigning reserve workers to line segments foremen. vs. (b) managing all the reserve workers of the line in one pool. A simulation study compares the effect on productivity of these two strategies.