By default, when a sensitivity is run, each parameter is varied up and down, with no intermediate steps. However, you can change this behaviour for all parameters within a particular Sensitivity element by changing the Steps and Perturbation settings in the Parameters dialog. When the value of a parameter is increased or decreased, this is normally calculated as a proportion of the original value (by default 1%). In the Details dialog, you can change the proportion used, or calculate the change on a different basis altogether (e.g., taking a specific value).