Common methods of measuring 'informed choice' in screening participation: Challenges and future directions.

There is general agreement among public health practitioners, academics, and policymakers that people offered health screening tests should be able to make informed choices about whether to accept. Robust measures are necessary in order to gauge the extent to which informed choice is achieved in practice and whether efforts to improve it have succeeded. This review aims to add to the literature on how to improve methods of measuring informed choice. We discuss and critique commonly-used approaches and outline possible alternative methods that might address the issues identified. We explore the challenges of defining what information should be provided about screening and hence understood by service users, appraise the use of ‘thresholds’ to define e.g. positive attitudes towards screening, and describe problems inherent in conceptualising ‘informed choice’ as a single dichotomous outcome that either does or does not occur. Suggestions for future research include providing greater detail on why particular aspects of screening information were considered important, analysing knowledge and attitude measures at an ordinal or continuous level (avoiding problematic decisions about dichotomising data in order to set thresholds), and reconceptualising informed choice as a multifactorial set of outcomes, rather than a unitary one.