A note on simulation for estimating the variance of throughput in flow lines with finite buffers

Although analytical approaches and exact solution methods are best for manufacturing system design, it is not easy when the systems become complex. Thus, approximation methods are required and the accuracies of the methods are analyzed by simulation. However, unlike the first order measures such as the mean of throughput, the second order measures such as the variance rate of throughput is difficult to be converged using simulation study. This paper introduces various phenomena empirically when the variance rate of throughput is estimated by simulation in flow lines.