Size matters – how big is big? Size estimation of physicians

Background In clinical practice, sizes are often described by comparative everyday objects. "Pinhead-sized tympanic membrane defect" or "cent-sized dehiscence" have found their way into clinical practice. But are we examiners really sure about the size of a pinhead? We want to investigate whether we are able to estimate absolute sizes sufficently and whether abstraction by everyday objects leads to an improvement of size-estimation by a web-based measurement method and questionnaire study.

Methods This is a prospective, monocentric, anonymous web-based study with 206 physicians between march and june ‘22. Participants estimated everyday objects (e.g.pea) as well as SI units (e.g.5mm) in real size using a slider on a pre-normed monitor. In addition, participants were asked to self-assess their estimation ability.

Results On average, the size of everyday objects and SI units were underestimated by about 15%. Self-assessment did not correlate with true estimation ability based on the measured parameters (p=0.96). Attendings considered themselves better estimators on average (p=0.01), with no differences in real estimation accuracy. The specialty had no influence on accuracy in our survey, whereby radiologists and neurosurgeons considered themselves as particularly good estimators.

Conclusion Even if the study has a humorous character, our results show a serious essence: There were partly highly significant underestimations, which could lead to wrong assessments and decisions in clinical everyday life. Thus,the recommendation of the authors is – independent of clinical experience/specialty – the use of standardized measuring instruments for size estimations if possible.

Publication History

Article published online:
12 May 2023