Development and Validation of the Determinants of Breast Cancer Treatment Initiation Scale.

Background and Purpose: Timely breast cancer treatment initiation after diagnosis is crucial for a better disease prognosis. The health belief model indicates that performing a health behavior is influenced by the person's health beliefs and cues to action. A scale to measure health beliefs and cues to initiate breast cancer treatment is needed. The purpose of this study is to describe the item development, content validation, and face validation of the new Determinants of Breast Cancer Treatment Initiation (DBCTI) scale. Methods: The items were developed based on a previous qualitative study. Eight experts tested the content validity index of the items (CVI). Five women with breast cancer evaluated the items for face validity. Results: Expert ratings and face validity feedback yielded 77 items, with an overall scale CVI of .97. The CVIs for the five subscales ranged between .93 and .99. Two items with a CVI less than .83 were retained for conceptual significance. Implications for Practice: The new DBCTI scale showed evidence of content and face validity. Further psychometric testing is warranted. This scale can be employed to assess factors influencing breast cancer treatment initiation in the clinical setting and to serve as an assessment tool to identify and address possible obstacles to early treatment initiation. Interventions can be designed to enhance early treatment initiation. .