Improving the reading ease of the Quick Inventory of Depressive Symptomatology - Self Report (QIDS-SR): Development and psychometric properties of an 'Accessible English' version

Self-report questionnaires are commonly used in depression research with little consideration of their reading ease. This study aimed to increase the reading ease of the commonly-used Quick Inventory of Depressive Symptoms Self Report (QIDS-SR) and assess the impact of the change in wording on the measure's psychometric properties. The study had three phases: 1) Flesh-Kincaid readability statistics of the original and modified wording were compared; 2) a sample of n = 95 participants rated the modified wording for perceived change in meaning and ease of understanding; 3) a second sample of n = 136 participants completed two versions of the QIDS-SR (original, modified, or one of each) alongside the Beck Depression Inventory (BDI). The internal consistency, test-retest reliability and convergent validity of the modified version were assessed. The modified QIDSSR had significantly higher reading ease, was considered easier to understand and was not perceived to have a significant change in meaning. Its psychometric properties were unaffected. The wording of the questionnaire was successfully simplified to increase its accessibility and this had no notable impact on the psychometric properties of the measure.