A sensitivity analysis should be undertaken on the initial ranking of options in order to test the robustness of the ranking produced. As a minimum the criteria which should be included in a sensitivity test are cost parameters (changes in capital expenditure, operating expenditure and revenue) and the weightings (where used) applied to the evaluation criteria.
For example, it may be possible to discern from the ranking that there is a significant margin of difference in the performance of say the top 4 options compared with the rest. The initial ranking should be subject to a further test of deliverability that includes consideration of site(s) availability and suitability, competition issues, planning framework, affordability and timing of delivery.