Background: Eating disorders are affecting an increasing number of high school students in Western and Asian countries. The availability of an effective screening tool is crucial for early detection and prompt intervention.
Objective: The objective of this study was to examine the validity and reliability of the SCOFF questionnaire for screening eating disorders in Hong Kong high school students.
Design: This study adopted a cross-sectional design to examine the psychometric properties of the SCOFF questionnaire.
Participants: A panel of 7 experts and 936 students of a high school participated in the study.
Method: The SCOFF questionnaire was translated into Chinese and back-translated into English to ensure the linguistic equivalence. A panel of 7 experts involved in the content validation of the SCOFF questionnaire. The Eating Disorder Examination-Questionnaire (EDE-Q) was used as the "reference standard" to assess its concurrent validity in 936 students of a high school. Its reliability was examined by internal consistency and the test-retest method at a 2-week interval and with 38 students.
Results: The SCOFF questionnaire achieved an agreement of 86-100% among the experts for the content relevance. Of 812 students (86.8%) who responded to this study, their SCOFF scores correlated significantly with their global scores on the EDE-Q (r=0.5, P<0.01). Students identified as potentially having eating disorders had significantly higher scores in the EDE-Q than those not identified as such by SCOFF. The SCOFF questionnaire demonstrated moderate test-retest reliability (ICC=0.66) and an acceptable internal consistency reliability (Cronbach's alpha=0.44-0.57) in comparing with previous studies.
Conclusion: The SCOFF questionnaire has acceptable psychometric properties in the Chinese culture. It will be useful for detecting potential eating disorders and assisting health promotion activity.