  In multi-criteria decision aiding, the Choquet integral has been used as an
aggregation operator to deal with interacting criteria, having as a requirement
a prior assumption of common scale for all the criteria. This restriction on
the adopted scale may be considered as a limitation in some practical problems.
In order to overcome this limitation, we propose a new Choquet integral
formulation, specific for sorting problems, that constructs a common scale from
heterogenous scales using the framework of the FlowSort method. We also
introduce a new outranking degree based on the Choquet integral preference
model, which allows the modeling of interacting criteria in FlowSort.
Therefore, the proposed approach can be seen either as an extension of FlowSort
for problems with interacting criteria or as a new Choquet integral formulation
for multi-criteria sorting problems with heterogeneous scales. Numerical
examples attest that the proposed approach is conceptually simple to be
implemented and acknowledge the importance of considering interaction between
criteria when it exists.
