Measuring Environmental Health Literacy - A Systematic Review of Represented Dimensions and Psychometric Characteristics of Evaluated Instruments in an Emerging Field.

Environmental health literacy (EHL) encompasses the skills and competencies to search for, understand, assess, and apply information and knowledge about the environment and its impact on human health. The development and availability of concept-based, psychometrically sound methods to measure EHL are crucial for advancing research and assessing the impact of public health programs in prevention. Guided by the PRISMA-COSMIN guidelines, a systematic search of three databases was conducted (MEDLINE, LIVIVO, PsycINFO). Information on the characteristics, operationalization of EHL, and psychometric criteria was extracted. According to COSMIN, the psychometric properties were evaluated. Of 1,872 records, nine studies were included. Eight different EHL measures were identified. The instruments target either general EHL (n = 4) or specific environmental issues (n = 4), such as air pollution, drinking water contaminants, and phthalate exposure. Some instruments reported sufficient structural validity (n = 4) and internal consistency (n = 2), while content validity remained indeterminate (n = 8). Information on responsiveness, measurement error, and intercultural validity could not be obtained. Based on the quality assessment, no general recommendation for use can be derived. Future studies should focus on validating existing instruments, while the development of new tools should more comprehensively address relevant environmental factors. We also recommend that previously underexplored dimensions of EHL, such as self-efficacy and collective agency, should be given greater consideration.