Measurement properties of the Danish version of the Awareness and Beliefs about Cancer (ABC) measure

Background: The International Cancer Benchmarking Partnership aims to study international differences in cancer survival and the possible causes. Participating countries are Australia, Canada, Norway, Sweden, Denmark and the UK and a particular focus area is differences in awareness and beliefs about cancer. In this connection, the Awareness and Beliefs about Cancer (ABC) measure has been translated into multiple languages. The aim of this study is to appraise the translation process and measurement properties of the Danish version of the ABC measure. Methods: The translation process included forward and backward translations and a pilot-test. Data quality was assessed using survey data from 3000 Danish respondents and content validity indexes were calculated based on judgments from ten academic researchers. Construct validity was determined by a confirmative factor analysis (CFA) and exploratory factor analyses (EFA) using survey data and a known group comparison analysis including 56 persons. Test-retest reliability was assessed based on responses from 123 person whom completed the interview twice with an interval of 2-3 weeks. Results: The translation process resulted in a Danish ABC measure conceptually equivalent to the English ABC measure. Data quality was acceptable in relation to non-response to individual items which was maximum 0.3%, but the percentage of respondents answering 'don't know' was above 3% for 16 out of 48 items. Content validity indexes showed that items adequately reflected and represented the constructs to be measured (item content validity indexes: 0.9-1.0; construct content validity indexes: 0.8-1.0). The hypothesised factor structure could not be replicated by a CFA, but EFA on each individual subscale showed that six out of seven subscales were unidimensional. The ABC measure discriminated well between non-medical academics and medical academics, but had some difficulties in discriminating between educational groups. Test-retest reliability was moderate to substantial for most items. Conclusions: The Danish ABC measure is a useful measurement that is accepted and understood by the target group and with accepted measurement criteria for content validity and test-retest reliability. Future studies may further explore the factorial structure of the ABC measure and should focus on improving the response categories.