a review of outcome measures Measuring peoples' understanding of the effects of treatments: a review of outcome measures Astrid Austvoll-Dahlgren, PhD, The Norwegian Knowledge Center for the Health Services Astrid.Austvoll-Dahlgren@nokc.no Allen Nsangi, Makerere University, Uganda Professor Andy Oxman, The Norwegian Knowledge Center for the Health Services Objective: The aim of this project is to provide a systematic overview of outcomes and outcome measurements used in studies evaluating or mapping peoples‘ understanding of the effects of treatments, which will inform future research in this area. Background: Being able to critically appraise claims about treatment effects is crucial for informed decision making. Studies mapping or evaluating people's understanding of the effects of treatments have not been measured consistently, and are characterised by differences in terminology and parallel discourses. Such inconsistencies are to some extent attributable to different research areas and disciplines being responsible for studies that have often focused on a specific concept, such as the understanding of numeracy. Methods: We conducted a systematic search in Cochrane Library (CDSR, DARE, HTA, CENTRAL, Method studies) MEDLINE In-Process & Other Non-Indexed Citations, and MEDLINE 1946 to Present (Ovid), ERIC 1966 to present (ProQuest). We reviewed the available evidence to identify outcomes and outcome measures used in studies evaluating peoples' understanding of the effects of treatments. In order to identify unpublished studies, we also contacted key researchers working in related research areas such as health literacy and training of patients and consumers in evidence-based medicine, including members of the Cochrane Consumer group and the Nordic Health Literacy Network. We included all relevant systematic reviews, trials and observational studies evaluating or mapping peoples understanding of the effects of treatments. The lead author in addition to one more researcher reviewed all references independently, extracted all outcomes in the included studies and entered these in a matrix to present an overview of the outcomes, to explore overlaps, inconsistencies and lack of evidence. Results: We identified 2961 references, of which nearly 70 were systematic reviews of studies mapping or evaluating specific concepts. All outcome measures evaluating the identified outcomes was presented in a table, and described according to the following criteria: which domains are captured, for which target population is the outcome measure intended, and are the outcome measures dichotomous or continuous, and subjective or objective. The indentified studies included outcomes and outcome measures belong to several overlapping research fields including; health literacy, decision aids, education in evidence based practice, numeracy, science education and informed consent. Conclusion: This review provides a systematic overview of outcomes and outcome measurements used in studies evaluating or mapping peoples‘ understanding of the effects of treatments, which will inform future research in this area.