CONTEXT: Medical screening tasks are often difficult, visual searches with low target prevalence (low rates of disease). Under laboratory conditions, when targets are rare, nonexpert searchers show decreases in false-positive results and increases in false-negative results compared with results when targets are common. This prevalence effect is not due to vigilance failures or target unfamiliarity. OBJECTIVE: To determine whether prevalence effects could be a source of elevated false-negative errors in medical experts. DESIGN: We studied 2 groups of cytologists involved in cervical cancer screening (Boston, Massachusetts, and South Wales, UK). Cytologists evaluated photomicrographs of cells at low (2% or 5%) or higher (50%) rates of abnormality prevalence. Two versions of the experiment were performed. The Boston, Massachusetts, group made decisions of normal or abnormal findings using a 4-point rating scale. Additionally, the group from South Wales localized apparent abnormalities. RESULTS: In both groups, there is evidence for prevalence effects. False-negative errors were 17% (higher prevalence), rising to 30% (low prevalence) in the Boston, Massachusetts, group. The error rate was 27% (higher prevalence), rising to 42% (low prevalence) in the South Wales group. (Comparisons between the 2 groups are not meaningful because the stimulus sets were different.) CONCLUSIONS: These results provide the first evidence, to our knowledge, that experts are not immune to the effects of prevalence even with stimuli from their domain of expertise. Prevalence is a factor to consider in screening for disease by human observers and has significant implications for cytology-based cervical cancer screening in the post-human papillomavirus vaccine era, when prevalence rates of high-grade lesions in the population are expected to decline.
CONTEXT: Medical screening tasks are often difficult, visual searches with low target prevalence (low rates of disease). Under laboratory conditions, when targets are rare, nonexpert searchers show decreases in false-positive results and increases in false-negative results compared with results when targets are common. This prevalence effect is not due to vigilance failures or target unfamiliarity. OBJECTIVE: To determine whether prevalence effects could be a source of elevated false-negative errors in medical experts. DESIGN: We studied 2 groups of cytologists involved in cervical cancer screening (Boston, Massachusetts, and South Wales, UK). Cytologists evaluated photomicrographs of cells at low (2% or 5%) or higher (50%) rates of abnormality prevalence. Two versions of the experiment were performed. The Boston, Massachusetts, group made decisions of normal or abnormal findings using a 4-point rating scale. Additionally, the group from South Wales localized apparent abnormalities. RESULTS: In both groups, there is evidence for prevalence effects. False-negative errors were 17% (higher prevalence), rising to 30% (low prevalence) in the Boston, Massachusetts, group. The error rate was 27% (higher prevalence), rising to 42% (low prevalence) in the South Wales group. (Comparisons between the 2 groups are not meaningful because the stimulus sets were different.) CONCLUSIONS: These results provide the first evidence, to our knowledge, that experts are not immune to the effects of prevalence even with stimuli from their domain of expertise. Prevalence is a factor to consider in screening for disease by human observers and has significant implications for cytology-based cervical cancer screening in the post-human papillomavirus vaccine era, when prevalence rates of high-grade lesions in the population are expected to decline.
Authors: J P O'Sullivan; R P A'Hern; P A Chapman; L Jenkins; R Smith; A al-Nafussi; M T Brett; A Herbert; M E McKean; C A Waddell Journal: Cytopathology Date: 1998-06 Impact factor: 2.073
Authors: Brandon D Gallas; Weijie Chen; Elodia Cole; Robert Ochs; Nicholas Petrick; Etta D Pisano; Berkman Sahiner; Frank W Samuelson; Kyle J Myers Journal: J Med Imaging (Bellingham) Date: 2019-01-21
Authors: Michael C Hout; Stephen C Walenchok; Stephen D Goldinger; Jeremy M Wolfe Journal: J Exp Psychol Hum Percept Perform Date: 2015-04-27 Impact factor: 3.332