The Effect of Proximity, Tall Man Lettering, and Time Pressure on Accurate Visual Perception of Drug Names

Abstract

Objective: The aim of this study is to assess the effect of proximity and time pressure on accurate and effective visual search during medication selection from a computer screen. Background: The presence of multiple similar objects in proximity to a target object increases the difficulty of a visual search. Visual similarity between drug names can also lead to selection error. The proximity of several similarly named drugs within a visual field could, therefore, adversely affect visual search. Method: In Study 1, 60 nonpharmacy participants selected a target drug name from an array of mock drug packets shown on a computer screen, where one or four similarly named nontargets might be present. Of the participants, 30 completed the task with a time constraint, and the remainder did not. In Study 2, the same experiment was repeated with 28 pharmacy staff. Results: In Study 1, the proximity of multiple similarly named nontargets within the specified visual field reduced selection accuracy and increased reaction times in the nonpharmacists. Time constraint also had an adverse effect. In Study 2, the pharmacy participants showed increased reaction times when multiple nontargets were present, but the time constraint had no effect. There was no effect of Tall Man lettering. Conclusion: The presence of multiple similarly named medications in close proximity to a target medication increases the difficulty of the visual search for the target. Tall Man lettering has no impact on this adverse effect. Application: The widespread use of the alphabetical system in medication storage increases the risk of proximity-based errors in drug selection.

A systematic literature review on strategies to avoid look-alike errors of labels

“…The majority of studies were conducted in the UK and USA, namely five each [18–20, 22, 24–27, 31, 32]. The remaining six studies were performed in Canada, China, India, Ireland, and Norway [17, 21, 23, 28–30].…”

“…Some studies tested additional conditions such as with and without time pressure or previous knowledge about the purpose of Tall Man lettering [19, 27]. The most common outcomes tested were error rate and response time.…”

“…In three out of nine studies, response time was significantly shorter for Tall Man lettering compared to non-Tall Man lettering [19, 24, 32]; in four studies, there was no difference [18, 19, 27]; and in two studies, response time was significantly longer for Tall Man lettering [24, 28]. One study found that when participants did not know about the purpose of Tall Man lettering, the response times were similar for lowercase and Tall Man lettering.…”

SIMMEON-Prep study: SIMulation of Medication Errors in ONcology: prevention of antineoplastic preparation errors

“…The implication of human factors and behaviour in the occurrence and prevention of error remains inadequately studied . Several simulation programs, which have proved successful in civil aviation, in the army and more recently in health care, are effective in preventing medical errors and improving patient safety .…”

Does Tall Man lettering prevent drug name confusion errors? Incomplete and conflicting evidence suggest need for definitive study

“…In one study, when participants were not told beforehand about Tall Man's purpose, Tall Man lettering was not effective, but then in a follow-up study, when participants were told, Tall Man was effective 16. Elsewhere, failure to find a positive effect of Tall Man lettering was attributed to participants not knowing the purpose beforehand 19. It could be also argued that studies in which participants know the purpose beforehand better simulate real-world clinical practice because most healthcare professionals will know the purpose of Tall Man lettering.…”