Evidence gap maps: a visual tool for promoting evidence and monitoring gaps in research
Background: Evidence Gap Maps (EGMs) are visual tools that present the available evidence on different thematic areas and highlight gaps for future research. EGMs, constructed by international Non-governmental Organisation Sightsavers, summarize, appraise, and present evidence from systematic or literature reviews across different eye health conditions, including cataract, refractive error, glaucoma, diabetic retinopathy, and trachoma. Updating an EGM periodically allows us to monitor changes to the extent and quality of the evidence base and to refine the focus for future research. This presentation will focus on the methods used to develop and update the EGMs and discuss their potential in promoting rigorous, high-quality research and countering misinformation.
Methods: After conducting a comprehensive literature search, we sift and extract data from all relevant reviews. Critical appraisal is conducted independently using the Supported Use of Research Evidence checklist, allowing us to attribute a confidence level of low, medium, or high to the review. We assessed the strength of evidence of the effect of each review. If the review reaches a conclusive answer to their research question using the available evidence, the evidence is classified as strong. If they were unable to answer the question because of insufficient evidence, the evidence is classified as weak. Otherwise, the evidence is inconclusive. Each review is displayed in a matrix where the columns show thematic areas relevant to the eye health condition, labelled as sectors and subsectors, and the rows show the strength of evidence. Updates are conducted in the same way as the original EGMs. Changes to the evidence base were assessed by comparing the numbers and percentages of included reviews across a number of areas, including the thematic focus, geographic representation, strength of evidence of effect, and methodological quality. Conclusion and patient and healthcare consumer involvement: EGMs allow policymakers and clinicians to plan their interventions based on the most up-to-date knowledge and high-quality research, which helps ensure that patients receive the best possible care. Updating the EGMs periodically allows researchers to monitor changes in the extent and quality of systematic review evidence and to prioritise future work to improve the evidence base and to close evidence gaps.