Step 4 – Use the right inclusion/exclusion criteria – a pilot phase?
Naturally, the right inclusion and exclusion criteria must be set a priori and stated in the methodology before the data extraction begins, if the analysis is to be systematic and consistent. However, a pilot phase can be a useful means of determining if the searches have in fact yielded the relevant results, and have not excluded anything important. This helps prevent a change in plan after the analysis begins, when it is discovered that the criteria are too stringent or are so broad as to waste the researcher’s time. A pilot phase has the advantage of ensuring that a single search sequence used on a particular day can then be replicated if need be by other researchers, giving you confidence that your final search methods will be transparent and repeatable. A rapidly conducted pilot study would help determine if more stringent exclusion criteria could limit the number of papers to be analysed, without losing important information. This may reduce the number of papers to a more manageable amount.
In summary then, these are the first 4 steps to get right in the lengthy process of performing a good literature review. Good luck with your searches, and if you want any more information about how to put together a good search there are several people to talk to at Rx who would be happy to give you more insights. For getting the question right, contact Ruth or Caroline; for deciding on databases and perfecting search strings, William is your man. And we can all help with inclusion and exclusion criteria.