Population pharmacokinetic (PK) approaches were first introduced in the 1970s mainly as a tool to allow extraction of meaningful and useful PK data from sparse observational data arising from diverse clinical studies (1). It was quickly taken up by academicians and used to determine the PK and pharmacokinetics/pharmacodynamics (PK/PD) of drugs given to patients with more robustness than individual type approaches. Indeed, it was rapidly shown that population approaches were likely better than the standard two-stage approach for determining the PK of a compound from simulated data sets (2,3).