Extended SAFPHR (Systems Analysis for Formal Pharmaceutical Human Reliability): Two approaches based on extended CREAM and a comparative analysis

Medication errors originating in community pharmacies can cause severe harm. To provide pharmacies with the ability to accurately predict error rates, understand why errors are occurring, and mitigate problems, we developed a new human reliability analysis (HRA) called the Systems Analysis for Formal Pharmaceutical Human Reliability (SAFPHR). Through the combination of HRA that is based on the Cognitive Reliability and Error Analysis Method (CREAM) and probabilistic model checking (an automated method for proving properties about stochastic systems), SAFPHR is able to address the limitations of previous HRAs. The previous, "basic" version of SAFPHR was based on the "basic" version of CREAM. With this, we predicted a realistic range of medication error rates for a typical US community pharmacy dispensing procedure. However, basic SAFPHR was not capable of providing point estimates except through averaging. In this research, we attempted to address this limitation by making SAFPHR compatible with the two variations of extended CREAM, enabling SAFPHR to make point predictions about pharmacy dispensing error rates. Then, to determine which of the versions of SAFPHR produce the most accurate predictions, we compare results from each approach to aggregate rates published in the community pharmacy literature. In this, arithmetic averages across basic SAFPHR's range were consistently the most accurate for the overall error rate and rates of errors originating at different stages of the dispensing procedure. We use this finding to derive recommendations from basic SAFPHR for improving the reliability of community pharmacy dispensing with the ambition of improving patient health and safety.