Response to "Collating science-based evidence to inform public opinion on the environmental effects of marine drilling platforms in the Mediterranean Sea".

In their recent review article, Mangano and Será (Journal of Environmental Management, 188:195-202) collate and describe the evidence base relating to the impacts of marine drilling platforms in the Mediterranean. The authors claim to have undertaken a systematic map using the Guidelines for Systematic Review in Environmental Management produced by the Collaboration for Environmental Evidence (CEE) as a basis for their methods. Here, I highlight major problems with their methods and the reporting of their activities. I demonstrate that a higher level of rigour and transparency is necessary for a true systematic map. Whilst their work is not without merit and may prove useful for decision-makers, their review could have been conducted and reported to a greater level of reliability. I stress the importance of transparency, comprehensiveness, and repeatability in ensuring that reviews are reliable and fit-for-purpose. I highlight the pitfalls of the authors' approach in terms of: question framing; searching for evidence; the definition of grey literature; key outputs from systematic maps; and the dangers of vote-counting.