Re-validation of the Cancer Research UK Cancer Awareness Measure 'plus' (CAM+): a study protocol

The Cancer Research UK Cancer Awareness Measure (CRUK CAM) was introduced in 2008 as the first psychometrically validated survey of public attitudes, awareness and behaviours across cancer prevention, screening and early diagnosis. CRUK regularly collects CAM data in the UK to inform strategic planning. The measure has been modified over time in response to changes in the research, policy and practice landscape. Our aim is to revalidate the most recent CAM 'Plus' (CAM+) to ensure the measure remains accurate, reliable, valid, and relevant over time.

There will be four phases, running from 2023 to 2026, with the CAM + being revised after each phase. Phase 1 will start by auditing the CAM + against a behaviour change framework, i.e., the COM-B, postulating that to engage in a Behaviour (B), a person must have the Capability (C) and Opportunity (O) to exhibit that behaviour, as well as the Motivation (M) to demonstrate it at a specific moment. This phase will also include (a) scoping literature reviews; (b) a face validity assessment, to check CRUK and scientific evidence needs and identify gaps in the survey; and, (c) a readability assessment using the Hemingway App to check for long complex sentences. Phase 2 will focus on content validity, using two stages of cognitive interviews with members of the public to assess comprehension and clarity. The first stage will use a 'Think Aloud' methodology to identify potential problem areas; while the second stage will use the four-stage model of cognitive interviewing to understand how people comprehend, retrieve, judge, and respond to questions. In Phase 3, we will conduct exploratory and confirmatory factor analysis to inform further refinements to the measure. In Phase 4, we will assess: (a) construct validity, by comparing responses of cancer experts and non-cancer experts; (b) reliability, using the test-retest approach; and (c) responsiveness, using sensitivity to change to questions in CAM+, following a brief intervention. Throughout the revalidation process we will be adhering to the standards set out in the COSMIN guidelines.