A Canadian perspective on the benefits and challenges with “big” secondary environmental data

Trina Rytwinski, Steven J. Cooke, Jessica J. Taylor, Dominique G. Roche and Joseph R. Bennett, Canadian Centre for Evidence-Based Conservation, Department of Biology and Institute of Environmental and Interdisciplinary Sciences, Carleton University, Ottawa, ON, Canada, Paul A. Smith and Greg W. Mitchell, Wildlife Research Division, Environment and Climate Change Canada, National Wildlife Research Centre, Ottawa, ON, Canada, Karen E. Smokorowski, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Sault Ste. Marie, ON, Canada, Kent A. Prior, Parks Canada, Gatineau, QC, Canada

Background/Question/Methods
For decades, critical appraisal and systematic synthesis of information have served as the basis for an evidence-based approach to global health care decisions. Now, evidence-based decision making involving systematic reviews is increasingly recognized as the gold standard synthesis method in environmental management and conservation. In North America, efforts to develop capacity for conducting systematic reviews and identifying mechanisms by which outcomes of such reviews can be used to inform policy and practice are still in their infancy. However, progress is ongoing. For example, institutions within the Canadian government, such as Parks Canada, Fisheries and Oceans Canada, and Environment and Climate Change Canada have recently begun integrating formal systematic reviews into their decision-making processes following guidelines developed by the Collaboration for Environmental Evidence (CEE). Here, we draw upon our experience conducting systematic reviews, systematic maps, narrative reviews, and stand-alone meta-analyses with the Canadian Centre for Evidence-Based Conservation (CEBC) to provide our perspective on some of the benefits and challenges with “big” secondary data.
Results/Conclusions
Using case studies of recently completed CEBC evidence syntheses, we will highlight (1) results using both large (e.g., 1199 studies) and small (e.g., 70 studies) bodies of primary literature, (2) how these results were used to help inform environmental management decisions, (3) how our approaches to synthesizing evidence were adapted in certain situations to improve their usefulness in addressing environmental management questions, and (4) some lessons learned along the way. Lastly, we will also identify the circumstances that can lead to ambiguity, bias, and the absence of additional evidence arising from systematic reviews and provide practical guidance to resolve or handle these scenarios when encountered. For instance, it is not uncommon for a systematic review to conclude that an evidence base is large but of low reliability or that it is sparse (e.g., one or two empirical studies on a particular taxa or intervention) and no additional evidence arises from a systematic review. In some cases, a systematic review highlights great variability in outcomes of primary studies, which generates ambiguity. Despite these challenges, practitioners must still make decisions. Waiting for new (high validity) research to be conducted is often unrealistic as many decisions are urgent. Our perspective attempts to highlight that, with evidence synthesis, there may be a need to balance the spirit of evidence-based decision-making and the practical reality that management and conservation decisions and action is often time sensitive.