Prescription legibility: bigger might actually be better

Drug errors are common and can be detrimental to patients, even resulting in death. Junior doctors write most prescriptions and are therefore responsible for most errors. There is little literature about the effect of legibility of the prescriber's handwriting on the rate of drug errors. Folklore would deem doctors' handwriting to be poorer than average; however, studies have shown this to be incorrect. In fact, handwriting in general has been shown to be poor.

A random sample of prescriptions from inpatient drug charts were chosen to provide a wide spread of legibility, with an even spread of the use of upper-case and lower-case lettering. Two cohorts of 13 junior doctors and 13 non-medical controls were recruited and asked to transcribe each of the prescriptions. Results were analysed for evidence of a statistical difference in correct transcription rate between lower-case or upper-case letters.

Non-medical participants correctly transcribed only 45% of prescriptions written in lower case. This rose to 66.5% for those written in upper case. This showed strong statistical significance, p<0.005. A statistical difference was also shown for differences in transcription by junior doctors (92.3% vs 97.8%, p=0.016).

Doctors must take responsibility for the quality of the prescriptions they write, to prevent avoidable drug errors. Legibility is improved by the use of capital letters. Therefore, we recommend that the use of upper cases should become routine practice when writing drug prescriptions.