An explanation device operates to generate explanatory information for a user regarding the cause of any demands that could not be satisfied by an automated supply chain optimizer. The explanation device identifies the cause for any unsatisfied demands by successfully relaxing various supply chain constraints while controlling the supply chain optimizer to re-optimize the supply chain subject to the relaxed constraints. If a previously unsatisfied demand is satisfied during re-optimization by relaxing a given constraint, then that constraint is deemed to have been a factor in the original, unsatisfied demand. If so, explanatory information is output to the user regarding the constraint. The amount by which the constraint was originally violated during the initial optimization may also be determined and provided to the user as further explanatory information.