What is new?
Key finding A key finding of this critical appraisal was that limited empirical evidence exists on the reliability and construct validity of health literacy measures. This raises uncertainty about the accuracy of data being produced in relation to health literacy levels at an individual and population level. Furthermore this research demonstrates that great variation exists across indices in terms of content across domains, methods of item selection and scoring and how individuals are categorised or classified in terms of health literacy levels. The variation and weak psychometric data makes it difficult to compare or pool results across studies and hinders the establishment of clear benchmarks for policy and program development aimed at addressing suboptimal health literacy. This appraisal, using a structured methodological framework, provides new and synthesised information for researchers and clinicians on the strengths and limitations of current indices of health literacy. Although previous literature acknowledges the narrow approach taken to the measurement of health literacy, the systematic presentation of the validity, reliability and applicability of these instruments provides more detail relating to psychometric properties of existing instruments. This review will support clinicians, researchers and policymakers to qualify the findings and recommendations derived from the use of health literacy indices. Further research is required to obtain empirical evidence across different populations and settings of the construct validity and reliability of existing measures. New measures which incorporate broader constructs of health literacy are required and are needed to advance this field.
What this adds to what is known?
What is the implication, what should change now?