Development and psychometric evaluation of the cancer screening behavioral decision-making scale for high-risk populations: a methodological study

Behavioral decision-making plays a critical role in the willingness of high-risk populations to participate in cancer screening. However, there is currently a lack of valid and reliable tools for evaluating the level of cancer screening behavioral decision-making in these populations. This study aimed to develop an instrument for assessing the level of cancer screening behavioral decision-making in high-risk populations. Scale development was conducted in six phases: (1) a literature review and establishment of the Protective Action Decision Model as the theoretical framework; (2) individual interviews to generate an initial item pool; (3) two rounds of Delphi consultation and a pilot study to refine the items; (4) item reduction; (5) and (6) psychometric evaluation using both Classical Test Theory (CTT) and Item Response Theory (IRT). A total of 766 high-risk individuals were recruited through purposive sampling. The data were analyzed using SPSS 26.0, Mplus 6.1, and R 4.4.3. The CTT analysis included assessments of construct validity, content validity, known-group validity, and reliability. IRT analysis was used to examine item discrimination, difficulty parameters, item information, item characteristic curves, marginal reliability, and differential item functioning. The final scale comprises 24 items across five dimensions, explaining 62.61% of the total variance. Cross-validation using exploratory and confirmatory factor analyses supported the proposed five-factor structure. The Cronbach’s α and McDonald’s ω coefficients for the subscales ranged from 0.729 to 0.904 and 0.712 to 0.817, respectively. The scale’s average content validity index was 0.925, with item-level indices ranging from 0.867 to 1.00. Most items demonstrated strong psychometric performance, with favorable item characteristic curves and information functions. The CSBD Scale has strong psychometric properties and is a reliable, valid instrument for assessing behavioral decision-making in cancer screening. This tool may provide a foundation for developing targeted interventions to improve screening participation, ultimately enhancing early detection and survival outcomes.