Ecosim does not (yet!) include any formal sensitivity analysis. Experience shows, however, that of the extra parameters added to those required by the typical Ecopath models, the most sensitive parameter is the Vulnerability setting. This parameter expresses the exchange rate between the prey being in vulnerable and non-vulnerable states (see Figure 3.3 in Vulnerabilities in Ecosim).
The vulnerability parameter is in general not subject to direct measurement. There are, however, other ways of estimating it, and Ecosim includes two independent methods of estimation:
It is possible and indeed recommended to use all of these methods to obtain estimates for the vulnerability parameters.