The study, first published in 2006, looks at how we should evaluate electronic prescribing systems in hospitals, particularly to improve patient safety. It provides an evaluation framework, compares methodologies to detect prescribing errors and describes the advantages of approaching evaluation of these systems from a sociotechnical perspective. Two electronic prescribing systems are studied using simultaneous quantitative and qualitative approaches. Electronic prescribing systems can reduce the incidence of prescribing error, however their implementation is not straight forward and they should be considered a constant 'work in progress'.