Validity and reliability of observational methods for studying medication administration errors.

The validity and reliability of observational methods for studying medication administration errors (MAEs) were studied. Between January and June 1998, two pharmacists observed consecutive drug administration rounds by nurses on two wards in a U.K. hospital and recorded all MAEs identified. The observers intervened in cases of potentially harmful errors. MAE records were audited to determine the percentage of omitted doses for which a corresponding reason was documented for the observation periods and for nonobservation periods. Error rates for each drug administration round were analyzed according to whether they were for the nurse's first, second, third (and so on) observed round. Error rates were calculated before and after the first intervention with nurses for whom an intervention was made. Observer reliability was calculated by comparing the rates of errors identified by the two observers. There was no difference between the observation and nonobservation periods in the percentage of omitted doses for which a reason was documented, and there was no change in the error rate with repeated observations. There was no difference in error rates before and after the first intervention for each nurse. There was also no difference in error detection between the two observers and no change with increasing duration of observation. Observation of nurses during drug administration at a U.K. hospital did not significantly affect the MAE rate; nor did tactful interventions by the observers. Observer reliability was high. Concerns about the validity and reliability of observational methods for identifying MAEs may be unfounded.