  The technician routing and scheduling problem (TRSP) consists of technicians
serving tasks subject to qualifications, time constraints and routing costs. In
the literature, the TRSP is solved either to provide actual technician plans or
for performing what-if analyses on different TRSP scenarios. We present a
method for building optimal TRSP scenarios, e.g., how many technicians to
employ, which technician qualifications to upgrade, etc. The scenarios are
built such that the combined TRSP costs (OPEX) and investment costs (CAPEX) are
minimized. Using a holistic approach we can generate scenarios that would not
have been found by studying the investments individually. The proposed method
consists of a matheuristic based on column generation. To reduce computational
time, the routing costs of a technician are approximated. The proposed method
is evaluated on data from the literature and on real-life data from a
telecommunication company. The evaluation shows that the proposed method
successfully suggests attractive scenarios. The method especially excels in
ensuring that more tasks are serviced but also reduces travel time with around
16% in the real-life instance. We believe that the proposed method could
constitute an important strategic tool in field service companies and we
propose future research directions to further its applicability.
