People who are sceptical of the Mauritius modelling exercises have pointed out rightly that the specific case may have little relevance for sustainable development planning in general. The problem lies in the simplicity of Mauritius. It is a small island state, with a relatively simple set of conditions. Air pollution is no problem, the full economy can be captured quite well with 15 sectors, and the entire country can be treated as one region. The fate of the Enhancement of Carrying Capacity Options (ECCO) model provides support for the advantages of simplicity. Originally it was planned to develop and run the ECCO model on Mauritius. Even the simplicity of Mauritius could not help the ECCO model, however, and the plan was apparently abandoned. It might be that ECCO will ultimately prove useful, for its use of energy units rather than prices. For the moment, however, it must be judged too inaccessible to have much value.