Two recent surveys have reported widely differing prevalence rates for posttraumatic stress disorder (PTSD) within the U.K. police force. Stevelink et al. (2020) reported a rate of 3.9% whereas a survey conducted for the charity Police Care UK reported a rate of 20.6%. In this comment we discuss how definitions and methodological factors can impact prevalence rates. We consider a number of possible reasons for the discrepancy between the surveys, and conclude that it is most likely a method artefact. Stevelink et al.’s survey reported the prevalence of recent-onset DSM-IV PTSD only, whereas the Police Care UK survey reported the total ICD-11 PTSD and Complex PTSD prevalence, regardless of when in the person’s career the traumatic events occurred. Analysing the Police Care UK data using Stevelink et al.’s procedures produced practically identical prevalence rates, suggesting that the discrepancy was apparent rather than real.