PRISMA, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, is a minimum set of items for reporting in systematic reviews and meta-analysis. Even when your goal isn't a systematic review or a meta-analysis, this set of items can also help you to search in more systematic way and to make your search more transparent and reproducable (also for your future self!).
The checklist consists of 27 items. It guides you through the choices you have to make when you do a literature review. For example: what are criteria for eligibility (when do you include a paper or not), which databases have you used, what was the search strategy? This will make your literature review more systematic, better structured, and it will be easier to write down the steps in your paper or article.
The flow diagram shows the ‘flow’ of information in the different phases of a systematic review, by showing the number of records identified, included and excluded, and the reasons for exclusions. In the academic literature you will find a lot of variants of the flow diagram.
In 2021, the PRISMA extension for searching was published: a checklist of 16 items to report literature searches in systematic reviews. They are more specific than the PRISMA Statement.
In the PRISMA flow diagram you summarize the study selection process. In the diagram you report:
This is the visualization of these steps in the flow diagram as described in the PRISMA statement:
Source: Moher D., Liberati A., Tetzlaff J., Altman D.G., The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and MetaAnalyses: The PRISMA Statement. PLoS Med 6(7): e1000097. https://doi.org/10.1371/journal.pmed.1000097
In the other tabs you can see examples of how the PRISMA flow diagram is applied in academic articles.
Source: Bom, J., Bakx, P., Schut, F., & van Doorslaer, E. (2018). The impact of informal caregiving for older adults on the health of various types of caregivers: A systematic review. The Gerontologist, 59(5), e629-e642. https://doi.org/10.1093/geront/gny137
Source: Igalla, M., Edelenbos, J., & van Meerkerk, I. (2019). Citizens in action, what do they accomplish? A systematic literature review of citizen initiatives, their main characteristics, outcomes, and factors. VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations, 30(5), 1176-1194. https://doi.org/10.1007/s11266-019-00129-0
Source: Jones, A., Remmerswaal, D, Verveer, I, Robinson, E., Franken, I.H.A, Wen, C.K.F., & Field, M. (2019). Compliance with ecological momentary assessment protocols in substance users: a meta-analysis. Addiction, 114(4), 609-619. https://doi.org/10.1111/add.14503