Questionnaire validation practice within a theoretical framework: a systematic descriptive literature review of health literacy assessments.

The health and health equity of individuals and populations are increasingly dependent on decisions based on data collected through health assessments. An evidence-based theoretical framework provides structure and coherence to existing evidence and stipulates where further evidence is required to evaluate the extent to which data are valid for an intended purpose. This review demonstrates the use of the Standards' theoretical validity testing framework to evaluate sources of evidence reported for health literacy assessments. Findings indicate that theoretical validity testing frameworks are rarely used to collate and evaluate evidence in validation practice for health literacy assessments. Use of the Standards' theoretical validity testing framework would improve evaluation of the evidence for inferences derived from health assessment data on which public health and health equity decisions are based.