Utilisation of a think-aloud protocol to validate a self-reported periodontitis questionnaire.

ABSTRACT

OBJECTIVES: The gold standard approach to diagnose periodontitis is based on clinical examination and radiographic investigations. This, however, is expensive, tedious, and not feasible in population-level assessments. The self-reported periodontitis questionnaire offers great benefit to facilitate larger epidemiological surveys. There is limited evidence on cognitive validation of self-reported periodontitis questionnaire. This study employed a think aloud approach to investigate if participants interpreted, comprehended, and understood the items in a self-reported periodontitis questionnaire, in the same way as researchers' intended. METHODS: 20 adults, resident of the UK and fluent in English participated in online recorded think aloud interviews. The self-reported periodontitis questionnaire consists of 15 questions and 2 open ended questions. The interviews were then transcribed and coded by two independent researchers according to predefined categories representing comprehension and conventional content analysis was used to analyse open-ended data. RESULTS: The think aloud approach revealed that most of the questions in the self-reported periodontitis questionnaire were well understood by the participants. Two items, however, were identified as problematic one was misinterpreted, and another question was not understood by most of the participants. Qualitative conventional content analysis of open-ended questions reiterated and complemented the findings of the think aloud study. Further questions coded as problematic for 3 or more participants were then considered for rephrasing. CONCLUSIONS: This study revealed the interpretation and understanding of self-reported periodontitis questions by English speaking UK residents and highlighted the probable reason for lower sensitivity values of the self-reported periodontitis questionnaire. CLINICAL SIGNIFICANCE: This study employed think-aloud approach to capture the thought process of the participants as they answered questions on self-reported periodontitis questionnaire. Overall, the questionnaire was well received by the participants, however, some questions were misunderstood/misinterpreted. This study highlights the potential information bias if participants do not understand the questions in epidemiological surveys.