What makes a tool appropriate to assess patient-reported outcomes of periodontal disease?

CONTEXT: Patient-reported outcomes (PROs) have become primary or secondary outcome measure in clinical trials and epidemiological studies in Medicine and Dentistry in general and Periodontology in particular. PROs are patients' self-perceptions about consequences of a disease or its treatment. They can be used to measure the impact of the disease or the effect of its treatment. There are insufficient data in Periodontology related to scale development methodology although, recently, there is an increase in the number of published studies utilizing such tools in major journals. AIM: This paper is an overview of the development methodology of new PRO tools to study the impact of periodontal disease. MATERIALS AND METHODS: The iterative process begins with a research question. A well-constructed a priori hypothesis enables validity assessment by hypothesis testing. The qualitative steps in item generation include literature review, focus group discussion, and key informant interviews. Expert paneling, content validity index, and pretesting are done to refine and sequence the items. Test–retest reliability, inter-rater reliability, and internal consistency reliability are assessed. The tool is administered in a representative sample to test construct validity by factor analysis. CONCLUSION: The steps involved in developing a subjective perception scale are complicated and should be followed to establish the essential psychometric properties. The use of existing tool, if it fulfills the research objective, is recommended after cross-cultural adaptation and psychometric testing.