The Validity and Reliability of the Turkish Version of the Combined Index of Severity of Fibromyalgia

The original form of the Combined Index of Severity of Fibromyalgia (ICAF) will be translated into Turkish by two Turkish mother tongue translators who also speak English in advanced level. Then these translations will be combined into one translation and translated back to English. These translations will send to 7 different health professions who had experience working with FMS patients. The pre-final version will be composed and tested on a group of patients with FMS. If necessary, readjustments will be made, and the final version will be investigated in FMS patients. Acceptability was assessed in terms of refusal rate, rates of missing responses, and administration time. Reliability was assessed using Cronbach's alpha and test-retest assessments. Re-test assessments will be conducted after one week from first assessment. Content validity was assessed by examining the floor and ceiling effects and skew of the distributions. Convergent and divergent validity was assessed by examining the Pearson's correlation coefficients. In addition, the confirmatory factor analysis will be done to evaluate the validity of ICAF. Responsiveness was determined by examining effect size (ES), standardized response means (SRM) and P values generated using Wilcoxon's test.