Screening Search Results: A 1-2-3 Approach

Having undertaken the search, the next step is to screen the results to find those that best answer the question. However, this is far more than simply scanning a list of papers for those that seem most applicable, it should be a highly structured and replicable process. An important part of this is the completion of the PRISMA flowchart, which shows the number of papers retrieved and excluded at each stage of the screening process. Completion of this is essentially mandatory for publishing a systematic review, and so careful record keeping is required of both numbers and reasons for decisions made. There are tools such as reference management software that can be useful for this task, as well as producing the final report. Using these from the beginning is worth the time that they take to learn. An often under-appreciated task is that of version control, remembering which is the final version of each document and when they were produced. The final report or paper will need to state the date of the final search, which may need updating prior to submission if the question is one that is producing data rapidly. Screening is probably the most labour-intensive stage of systematic reviewing. With a vast and ever-expanding amount of published literature, this can often be a long and burdensome process taking the reviewer from a large number of papers retrieved in a search to the often much smaller number that will be included in the review. A narrowly focused review question is no guarantee of a small set of relevant papers from the automated search, partly because of the vagaries of indexing, but also due to inconsistent use of terms around the world of research.