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. 2019 Jan 29;9(1):e024385. doi: 10.1136/bmjopen-2018-024385

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© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

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Data extraction process for included systematic reviews. All four authors will extract data from the first 10 systematic reviews. The remaining systematic reviews will be divided between the four review authors, and each author will have 1/3 of his/her studies reviewed by a second author to assess the level of agreement. If >90% agreement is reached, no further checks of data extraction process will be completed.