Design and development of scales in primary care: Practical steps and statistical methods

This article outlines the statistical methods and practical steps involved in designing and developing valid and reliable questionnaires in primary care. Based on literature review on questionnaire development and scale design, we proposed a standardized protocol for scale development in primary care. This process encompasses key practical steps and statistical methods, illustrated by cases from prior research. The recommended seven-step approach includes: (1) defining the construction of measurement; (2) generating the pool of items; (3) selecting the scoring system and response format; (4) pre-testing (assessing content validity and face validity, etc.); (5)eliminating items by item analysis; (6)evaluating the scale initially, including evaluating the reliability and validity of the scale, and factor analysis or Rasch analysis; (7)re-evaluating the scale to re-examine the nature of the scale, including retesting reliability and constructing validity. In conclusion, scale development studies should adhere to standardized procedures, and the integrated use of Rasch model and factor analysis can make the measurements more objective.