This paper proposes a tool for multi-criteria decision aid to be referred to as a reasoning map. It is motivated by a desire to provide an integrated approach to problem structuring and evaluation, and in particular, to make the transition between these two processes a natural and seamless progression. The approach has two phases. In the first one, the building of a reasoning map supports problem structuring, capturing a decision maker's reasoning as a network of means and ends concepts. In the second phase, this map is enhanced, employing a user-defined qualitative scale to measure both performances of decision options and strengths of influence for each means-end link. This latter phase supports the decision maker in evaluating the positi...