Improving the quality of data in a computerised patient master index: implication for costs and patient care.

This study was designed to test the accuracy and completeness of nominal identifying data recorded on a hospital patient master index (PMI) and to estimate the cost-effectiveness of using patient questionnaires for improving quality of data. The study showed that the design of any PMI should include a method of obtaining and storing the last date at which a patient's details were confirmed as correct, a prompt system for identifying missing data and a routine report on completeness and inconsistencies within the data. Both accuracy and completeness of patient identification can be improved by the use of patient questionnaires. The cost of their use is more than matched by the savings obtained from complete accurate data. The use of computer produced questionnaires also reduces the need for peak time activity on busy computer systems.