Validation study of the Fertility Problem Inventory in Iranian infertile patients

Introduction: Developing a tool for measuring patient's problems is a vital step in the process of infertility treatment and research. Fertility Problem Inventory (FPI) is a questionnaire, which was made by Newton in 1999 to detect fertility problem associated within fertile couples, including 46 questions and five domains. Since validity and reliability of any instrument should be evaluated in the new environment and culture, the aim of this study was to assess the validity and reliability of the FPI in Iranian infertile couples. Materials and methods: Four hundred and ten patients in different stages of infertility treatment filled Fertility Problem Inventory. Forty-five patients answered the questionnaire twice at an interval of 2 weeks. Reliability and validity of the questionnaire were measured by Cronbach's alpha, interclass correlation, test retest, inter-rater agreement (IRA), exploratory factorial analyses and multi-trait scaling analysis. Results: Using a conservative approach, the IRA for the overall relevancy and clarity of the tool was 88.34% and 92.14%, respectively. Overall appropriateness and clarity were 92.23% and 94.48%, respectively. Overall integrity of the instrument was determined to be 87%. Cronbach's alpha coefficient was greater than 70% for all domains. The ICC ranged between 0.78 (Relationship concern) and 0.92 (Sexual concern). Exploratory factorial analyses demonstrate five fields suitable for instrument. The correlation of each item with its own scale (Rho ⩾ 0.4) represented a high convergent validity. In the discriminant validity of the tool, the correlation of each item with its own hypothesized domain was also greater than its correlation with other areas of the questionnaire. Conclusion: The results showed that Persian version of the FPI is a reliable and valid instrument for measuring the fertility problems in infertile patients.