Background: Cochrane review groups are encouraged to prioritise reviews that are likely to include studies over those that might not, but questions that identify no trials can be important to people making healthcare decisions. ‘Empty’ reviews based on comprehensive literature searching, especially those that have been identified in prioritisation exercises, can confirm and highlight important research gaps and inform the design of future trials.
Within Cochrane ‘empty’ reviews are subject to the same authoring and editorial requirements as reviews with included studies. This conflicts with the founding principle of Cochrane and the strategy to 2020 which encourages prudent use of resources.
Objectives: To develop and evaluate new approaches to ‘empty’ reviews
Methods:We will collect data about the time taken for protocol and review development of recent ‘empty’ Airways Group reviews. We will also look at our review proposals' log to assess the number of times titles were deemed clinically important but rejected because no trials were anticipated.
Results: We will put forward alternative approaches to ‘empty’ reviews. Our criteria will be:
1. maintains methodological integrity up to the point that a review can be confirmed empty;
2. minimises the workload for authors, editorial staff, peer reviewers and copy-editors;
3. publicises an important research gap quickly and succinctly to funders and researchers.
The approaches we describe aim to prevent research waste and are not intended for non-priority questions.
Conclusions: 'Empty' reviews for important research questions can be a useful tool to confirm and publicise research gaps.