Driven by necessity in our own complex review, we developed alternative systematic ways of identifying relevant evidence where the key concepts are generally not focal to the primary studies' aims and are found across multiple disciplines--that is, hard-to-detect evidence. Specifically, we sought to identify evidence on community engagement in…

Background: When literature searching for systematic reviews, it is good practice to search widely across different information sources. Little is known about the contributions of different publication formats (e.g. journal article and book chapter) and sources, especially for studies of people's views. Method: Studies from four reviews spanning…