5. Write the protocol

1. On Protocol (PICOS), give each element the words that name it and the words that rule a paper out: Population, Intervention, Comparator (left empty, it filters nothing) and Outcomes, then the study designs you want and the limits: years, language, kind of work, citations and open access.
2. Retracted, withdrawn and removed papers are always excluded, with that reason, unless you bring one back.
3. What it would do counts, before anything is saved, how many papers each rule would exclude. Press Save and screen to apply it. A paper with no abstract is never excluded on P, I, C or O, your own decisions are never changed, and every version of the protocol is kept.

To get words to start from, tick Suggest PICOS keywords from this search before you search. The words the 100 most cited papers use most are then offered under each element as Suggested chips: click one to add it, or Add all. They come from word statistics over titles and abstracts, so check each one; nothing joins your protocol until you click it.