  In our research we investigate the output accuracy of discrete event
simulation models and agent based simulation models when studying human centric
complex systems. In this paper we focus on human reactive behaviour as it is
possible in both modelling approaches to implement human reactive behaviour in
the model by using standard methods. As a case study we have chosen the retail
sector, and here in particular the operations of the fitting room in the women
wear department of a large UK department store. In our case study we looked at
ways of determining the efficiency of implementing new management policies for
the fitting room operation through modelling the reactive behaviour of staff
and customers of the department. First, we have carried out a validation
experiment in which we compared the results from our models to the performance
of the real system. This experiment also allowed us to establish differences in
output accuracy between the two modelling methids. In a second step a
multi-scenario experiment was carried out to study the behaviour of the models
when they are used for the purpose of operational improvement. Overall we have
found that for our case study example both discrete event simulation and agent
based simulation have the same potential to support the investigation into the
efficiency of implementing new management policies.
