Psychometric properties of the Female Sexual Function Index in the visual analogue scale format

The Female Sexual Function Index (FSFI) is the gold standard for evaluating female sexual function, yet it has not been validated in a visual analogue scale (VAS) format. The aim of the present study was to assess the psychometric properties of the FSFI applied to the VAS. METHODS: The study was conducted in three phases. In Phase 1, the instrument was adapted by two independent researchers, generating two versions, which were evaluated by a committee of six experts. The FSFI-VAS, resulting from this first phase, was used in a pilot study with 45 women. In Phase 2, the FSFI-Likert (original format) and FSFI-VAS questionnaires were administered to 246 women recruited to the study. Tests of reproducibility (test-retest/phase 3), internal consistency, discriminant validity and construct validity were applied. RESULTS: In Phase 1, the pilot study showed that there were no doubts and difficulties completing the FSFI-VAS. In Phase 2, the Spearman rank (validity) test showed high correlation between the total scores on the FSFI-Likert and FSFI-VAS (0.87). The results of the internal consistency test were between 0.66 and 0.88, and the results of the construct validity test indicated a good value (0.73). The discriminant validity test was also appropriate. In Phase 3, the lowest intraclass correlation coefficient value was 0.81. CONCLUSION: The FSFI-VAS has internal consistency, construct validity, discriminant validity and reproducibility adequate to assess female sexual dysfunction in young women.