A method is presented for incorporating subjective information into multi-objective evaluations. The method is based upon an eigenvalue and eigenvector analysis and structures multi-objective evaluations into a series of hierarchies in which pairwise comparisons are made. The method is demonstrated in the design of an aquatic monitoring network. Theoretical aspects of the approach are reviewed, including measures of subjective inconsistency, the sensitivity of inconsistency to pairwise comparisons, subjective scaling factors, and sensitivity of final, multi-objective weights. An interactive computer program for the application of the technique is described.