  Calculations of sensitivities of future experiments are a necessary
ingredient in experimental high energy physics. Especially in the context of
measurements of the neutrino oscillation parameters extensive studies are
performed to arrive at the optimal configuration. In this note we clarify the
definition of sensitivity as often applied in these studies. In addition we
examine two of the most common methods to calculate sensitivity from a
statistical perspective using a toy model. The importance of inclusion of
uncertainties in nuisance parameters for the interpretation of sensitivity
calculations is pointed out.
