Measuring pharmacist time use: a note on the use of fixed-interval work sampling.

Pharmacist time use was studied to examine whether fixed-interval work sampling would provide results comparable to those obtained when random-interval observations were used. The study was conducted over a three-month period using pharmacists in a single community pharmacy as subjects; similar study methods have been used in hospital settings. Four separate measures of pharmacist time use were designated: tasks, duties, competencies and productivity. In every case the fixed-interval method gave an estimate that was not significantly different from the random-interval procedure (alpha greater than 0.05, difference of proportions test). The findings suggest that pharmacist work patterns are not sufficiently cyclical to introduce a bias in work sampling by fixed intervals. Fixed-interval work sampling yields results comparable to those using the standard work sampling methods that rely upon random time periods between observations.