A robust schedule is defined as a schedule that is insensitive to unfo
reseen shop floor disturbances given an assumed control policy. In thi
s paper, a definition of schedule robustness is developed which compri
ses two components: post-disturbance make-span and post-disturbance ma
kespan variability. We have developed robustness measures and robust s
cheduling methods for the case where a ''right-shift'' control policy
is used. On occurrence of a disruption, the right-shift policy maintai
ns the scheduling sequence while delaying the unfinished jobs as much
as necessary to accommodate the disruption. An exact measure of schedu
le robustness is derived for the case in which only a single disruptio
n occurs within the planning horizon. A surrogate measure is developed
for the more complex case in which multiple disruptions may occur. Th
is surrogate measure is then embedded in a genetic algorithm to genera
te robust schedules for job-shops. Experimental results show that robu
st schedules significantly outperform schedules based on makespan alon
e.