Indeed, when you consider the traditional pharmacodynamic strategies within the context of the selection window, you see that unlike the MPC idea, they allow concentrations to be inside the window. In principle, you could have a very high value for a pharmacodynamic parameter and remain inside the window throughout therapy. This is because traditional pharmacodynamics is aimed at curing disease, not stopping resistance. In microbiological terms, traditional pharmacodynamics uses drug activity against susceptible cells (MIC) as its point of reference rather than activity against resistant mutants. Another important feature is the empirical nature of traditional pharmacodynamic measurements: values were obtained from clinical studies that revealed thresholds for successful therapy with respect to cure. For such studies patient numbers in the hundreds were deemed suitable. Using an empirical approach to define doses that will block the increase in resistance prevalence may require testing many, many more patients because on a per-patient basis resistance generally arises rarely.