Dutch Translation and Validation of the Treatment Expectation Questionnaire (TEX-Q)

The Treatment Expectation Questionnaire (TEX-Q) is a generic, multidimensional scale that measures patients' expectations of medical and psychological treatments. Currently, it is available in English and German only. This study aims to translate the TEX-Q into Dutch and evaluate its psychometric properties.

The TEX-Q was translated into Dutch following international guidelines for cross-cultural adaptation of self-report measures. The Dutch version was tested in 163 gynaecological outpatients starting new treatments, a group suitable for validation due to their diverse treatment experiences. Test-retest reliability was assessed in a sample of 25 gynaecological outpatients. We examined data completeness (ie, no missing data), score distributions, internal consistency, construct validity, confirmatory factor analysis (CFA), and test-retest reliability. Convergent validity was tested through correlations with Credibility/Expectancy Questionnaire (CEQ) and a single item from Brief Illness Perception Questionnaire (B-IPQ). Discriminant validity was assessed using Life Orientation Test (LOT-R), General Self-Efficacy Scale (GSES), Generalized Anxiety Disorder Scale (GAD-7) and Patient Health Questionnaire (PHQ-9).

Data completeness was 89%. Internal consistency, measured by Cronbach's α, was good for most subscales, with values mostly above 0.75, except for the 'Process" subscale (Cronbach's α = 0.55). The mean TEX-Q score showed moderate to strong correlations with CEQ and the B-IPQ item (r = 0.29-0.55). Correlations with discriminant measures like LOT-R, GSES, GAD-7 and PHQ-9 were low (r = 0.22, 0.23, -0.17, -0.14 respectively). CFA revealed an acceptable six-factor model. Factor loadings were high (minimum of 0.76). The test-retest reliability was moderate for the mean TEX-Q score (ICC = 0.72).

The Dutch version of the TEX-Q demonstrates acceptable validity and reliability, making it suitable for research and clinical practice in gynaecology. Further validation across diverse clinical populations is recommended.