Perceived understanding of pharmacology concepts from 3 cohorts of students. Students from three consecutive cohorts of the nurse prescribing course were asked to rate their understanding of pharmacology concepts on a five point scale (very well to very badly), on completion of the course. The figure shows the trends for 3 concepts. a) Understanding of first pass metabolism. b) Half-life of drugs. c) Plasma proteins and drug distribution. Cohort1 did not have access to any RLOs; cohort 2 had access to RLOs 'Understanding First Pass Metabolism' and 'Half Life of Drugs' and cohort 3 had access to all three RLOs. When RLOs were available the distributions shifted to the right away from the Badly/Very Badly descriptors to the Well/Very Well pole. The shifts were significant (Kruskal Wallis p < 0.05) for 'Understanding First Pass Metabolism' and 'Half Life of Drugs'.