Background/Question/Methods How can the academic enterprise of meta-analysis be made useful for managers, stakeholders and policy makers? Methodological advances including machine learning for literature searches, development of structural equation meta-analysis, incorporation of qualitative data, and meta-analysis of networks are promising developments. But while methodological developments in meta-analysis may be useful, even more important are developments in communication and implementation of practice standards for both meta-analysts and people implementing environmental decisions and management practices. Evidence-based practices in medicine were implemented slowly over time, but are now firmly established; the same is not yet true for environmental evidence-based decisions. Results/Conclusions Accounting for heterogeneity in responses to environmental practices and the need to take into account the specifics of individual cases are challenges for connecting research synthesis to environmental decisions and implementation (as they are for medicine). In restoration and conservation practice, ad-hoc implementation with no follow up is ubiquitous, particularly in local and small scale projects (with no scientific input, much less evidence-based). Meta-analyses often fail to follow protocols, and are lacking in transparency, follow poor analytic practices, and may fail to avoid biases. Practices can be upgraded and made more rigorous and accountable in both synthesis and environmental work. Longstanding challenges to carrying out syntheses remain, including unavoidably grossly unbalanced data structures and poor reporting quality of primary data (but primary data reporting is improving). Better implementation of meta-regression, more rigorous reporting standards for meta-analyses, and closer communication between people doing meta-analyses and stakeholders and users and of that information will help to make research synthesis much more useful to environmental practitioners, and further the implementation of evidence-based practices.
