Testing the Impact of Variations in Administration on the Kessler Psychological Distress Scale (K10).

Self-report measures are useful in psychological research and practice, but scores may be impacted by administration methods. This study investigated whether changing the recall period (from 30 to 7 days) and response option order (from ascending to descending) alters the score distribution of the Kessler Psychological Distress Scale (K10). Participants were presented with the K10 with either different recall periods or different response option orders. There was weak evidence of lower mean K10 scores when using a 7-day recall period than when using the 30-day recall period (B = 1.96, 95% CI [0.04-3.90]) but no evidence of a change in the estimated prevalence of very high psychological distress. Presenting the response options in ascending order did not affect mean scores, but there was weak evidence of reduced prevalence of very high distress relative to the descending order (incidence rate ratio [IRR] = 0.60, 95% CI [0.36-0.98]). These findings suggest that varying the administration method may result in minor differences in population estimates of very high psychological distress when using the K10.