This paper presents a methodology to analyze and/or design processes in which several stages are required to achieve the separation objectives and in which it is not possible to accurately define the operating conditions. This methodology is explained and applied to mineral flotation circuits but can be adapted and/or extended to other processes. The methodology considers the construction of a superstructure that includes alternatives to be analyzed, the representation of variables by distribution functions, a Monte Carlo simulation, the incorporation of indicators and a multi-objective analysis. From the obtained results, we conclude that the proposed methodology is a useful tool for analyzing and designing separation processes that include several stages, especially when there is uncertainty about the operating conditions of each stage. (C) 2012 Elsevier B.V. All rights reserved.