Development of a new version of the Bristol Stool Form Scale: translation, content validity, face validity, and reliability of the Persian version

OBJECTIVES: The Bristol Stool Form Scale (BSFS) is the most widely used scale for stool form assessment. This study aimed to translate the BSFS into the Persian version and determine its content validity, face validity, and reliability. DESIGN: Following permission, a forward–backward translation procedure was applied to translate the scale from English into Persian. A cross-sectional study was conducted on a sample of 210 participants from the general and gastrointestinal clinics of a teaching hospital affiliated with the Tehran University of Medical Sciences, Tehran, Iran, from January 2020 to August 2020. The samples were selected using convenience sampling. A group of 10 experts and 10 adults assessed content and face validity, respectively. The kappa index evaluated the reliability of the instruments. RESULTS: Participants’ mean (±SD) age was 37.62 (±8.87) years. Most of the participants (65.7%) were women. The highest percentage of concordance was 100% for stool type 7, and stool type 5 had the lowest concordance percentage (78.1%). The overall kappa index was 0.79. CONCLUSION: The Persian version of the BSFS is a valid and reliable measure for assessing stool form, and now it can be used in research and clinical practice.