Independence of the least/most preferred

Independence of the least/most preferred (ILMP) is satisfied when:

ILP: by adding a vote where candidate X has the worst possible rating (or rank), then that vote doesn't increase the winning chance of X.

and

IMP: by adding a vote where candidate X has the best possible rating (or rank), then that vote doesn't decrease the winning chance of X.

This criterion must apply regardless of how the other candidates are rated.

Meeting these criterion favors the use of intermediate ratings (if present in the voting system), reducing strategies such as min-maxing. Specifically, IMP avoids rating minimization, while ILP avoids rating maximization, and it's better.

Douglas Woodall's terms for these criteria are mono-add-top for IMP and mono-remove-bottom for ILP.