  Recently there have been fruitful results on resource theories of quantum
measurements. Here we investigate the number of measurement outcomes as a kind
of resource. We cast the robustness of the resource as a semi-definite positive
program. Its dual problem confirms that if a measurement cannot be simulated by
a set of smaller number of outcomes, there exists a state discrimination task
where it can outperforms the whole latter set. An upper bound of this advantage
that can be saturated under certain condition is derived. We also show that the
possible tasks to reveal the advantage are not restricted to state
discrimination and can be more general.
