This paper reports a key educational initiative undertaken by NHS Education for Scotland (NES), based upon recommendations from a 'Numeracy in Healthcare' consultation. We report here the design of a web-based technical measurement authentic assessment environment evolved from the safeMedicate suite of programs that provided a model for an environment within which a medication dosage calculation problem-solving (MDC-PS) benchmark could be articulated. A sample of 63 third-year pre-registration nursing students was recruited from four participating universities in the UK. A counterbalanced design was employed where the virtual authentic assessment environment was evaluated for internal consistency reliability and criterion-related validity against an objective structured clinical assessment (OSCE) undertaken in high-fidelity simulated clinical environments. Outcome measures indicated an extremely high internal consistency of the web-based environment. It was concluded that the combination of a web-based authentic assessment environment and further assessment of safe technical measurement interpretation and dexterity in a practice/practice simulation setting, populated with a benchmark and a criterion referenced rubric validated by the profession, is an innovative, viable, valid and reliable assessment method for the safe administration of medicines. As a result, the rubric for assessment of the appropriate range of calculation type and complexity informed the NMC's revised Essential Skills Clusters for Medicines Management (NMC, 2010a; NMC, 2010b). This inclusion provides a particularly strong example of both research directly influencing policy and of evidence-based regulation.