A survey of drug-dose calculation skills of Australian tertiary hospital doctors

Chanelle M Simpson, Gerben B Keijzers and James F Lind
Med J Aust 2009; 190 (3): 117-120.


Objective: To assess the ability of doctors to calculate drug doses and their workplace prescribing and calculation habits.

Design and setting: Prospective, questionnaire-based observational study conducted at a 570-bed teaching hospital in February 2007.

Participants: Convenience sample of 190 doctors, representing all acute medical and surgical disciplines and diverse levels of experience.

Main outcome measures: Demographic data, self-reported prescribing habits, predicted score on a 12-item test of ability to calculate drug doses, score considered adequate for peers, and actual score.

Results: 141 doctors (74%) completed the questionnaire. The mean actual score on the test was 72.5% (95% CI, 67.8%–77.3%), which was similar to the group’s mean predicted score (74.7%; 95% CI, 71.0%–78.5%) but significantly lower than the mean of the score they considered adequate (91.6%; 95% CI, 89.5%–93.8%) (P < 0.001). Subgroup analyses showed that senior doctors and those in critical care specialties (intensive care, emergency medicine and anaesthesia) achieved significantly higher actual scores than junior doctors and those in non-critical care specialties, respectively.

Conclusions: Doctors expect their colleagues to perform significantly better in a drug-dose calculation test than they expect to, or can achieve, themselves. Junior staff and those in non-critical care specialties should be targeted for education in the skill of drug-dose calculation to reduce the risk of medication error and its consequences.

  • Chanelle M Simpson1
  • Gerben B Keijzers2
  • James F Lind3

  • Department of Emergency Medicine, Gold Coast Hospital, Gold Coast, QLD.


No formal funding was sought for this study. We thank Dr Julia Crilly (Southern Area Health Service Emergency Department Clinical Network, Gold Coast Hospital, QLD) for her constructive input, and Dr Michael Steele (Bond University, Gold Coast, QLD) for reviewing the statistics.

Competing interests:

None identified.

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