  This article is concerned with the cost and time effective scheduling of
financial auditors with Integer Linear Programming. The schedule optimization
takes into account 13 different constraints, staff scarcity, frequent
alterations of the input data with the need to minimize the changes in the
generated schedule, and scaling issues. We compared two exact formulations of
the problem and we found a multi-commodity network flow formulation to be 24
times faster than a three-dimensional formulation. The delivered implementation
reduced time to the first schedule from 3 man-days to 1 hour and the schedule
update time from 1 man-day to 4 minutes.
