Much of job-shop scheduling research is based on the assumption that due dates are outside the control of the scheduler. The paper examines several procedures for specifying due dates, largely dependent on the expected processing time for jobs and on the level of congestion in the shop.
The effect of these procedures is examined in the case of three loading rules (FIFO, St and SI∗) On waiting times, on missing due dates and on notional cost functions. The study is based on numerous simulations of a given shop operating at various levels of load ratio and the case of a fluctuating load is briefly examined.