The guidelines for sensitivity analysis in project evaluation, as used in the Transit New Zealand Project Evaluation Manual (PEM), have been improved. This report provides an approach and methodology for sensitivity analysis that is of practical assistance in road project evaluation, and includes a revised version of Appendix A9, Sensitivity Analysis, for the PEM. Sensitivity analysis determines how sensitive a project analysis (e.g. its benefit:cost ratio) is to the effect of varying one input parameter at a time.
Issues of uncertainty in relation to road project evaluations are discussed, sensitivity analysis and other methods for dealing with such uncertainties are described as are the current sensitivity analysis procedures applied by Transit New Zealand.
Possible directions for development of improved procedures and the results of a consultation workshop are given, as well as recommendations for revising the prcedures and for on-going developments for project evaluation.