Variability in verbal eyewitness confidence

Typically, an eyewitness' verbal confidence is used to judge the reliability of their lineup identification. Across three experiments (N = 3976), we examined eyewitnesses' own words confidence in their lineup decision. For identification decisions (n = 1099), we identified 781 quantitatively unique responses representing 132 qualitatively unique statements that could be categorized into low, medium, and high confidence. For rejectors (n = 781), we identified 599 quantitatively unique responses representing 143 qualitatively unique responses that could be categorized into low, medium, and high confidence. Most participants provided a verbal phrase (e.g., pretty sure) but a significant proportion—34.19% of identifiers and 29.05% of rejectors—provided numbers (e.g., 80%). The present data highlight the variability in how confidence is expressed. The criminal justice system would benefit from guidance for interpreting verbal confidence. We provide a picture of eyewitnesses' verbal confidence as a first step.