Development and Content Validation of a Scale to Measure Fear of Physical Activity and Exercise in the Breast Cancer Population

Abstract

Purpose: To report the content validation of a tool that quantitatively measures the role of fear as a barrier to physical activity/exercise in breast cancer survivors. Number of Subjects: Twenty female breast cancer survivors participated in the cognitive interviews. Methods: The process of scale development for the Patient-Reported Outcome Measurement Information System (PROMIS) inventory guided the methodology. Phase I, item generation, began with a literature search exploring scales measuring fear in a variety of patient populations. The next step involved ‘binning’ items according to meaning and specific latent construct and ‘winnowing’ items that were duplicative, confusing, and lacking applicability. Stem and response options addressing intensity were selected. Phase II, content validation, was established through review by scale development and content experts and through cognitive interviews with breast cancer survivors. In the cognitive interview each scale item was reviewed by 5 survivors and analyzed by two interviewers. Results: Twenty one scales were identified from the literature search. From these scales, 116 items were extracted and assigned to appropriate bin constructs. Winnowing produced a scale of 28 items that decreased to 23 items following feedback from the content and scale development expert reviewers and the cognitive interviews. The final scale used a 0 to 4 Likert Scale to measure intensity of concern about participating in physical activity and exercise, and was named the Fear of Physical Activity/Exercise Scale - Breast Cancer (FPAX-B). Conclusions: Content validity is established. Phase III will establish psychometric properties consisting of construct validity with factor analysis, Cronbach's alpha, convergent and divergent validity using a target population of 400 breast cancer survivors.