Table 1. Registration records in the PROSPERO and non-PROSPERO platforms.
| Year | 2011 (n = 288) |
2012 (n = 769) |
2013 (n = 1,534) |
2014 (n = 2,713) |
2015 (n = 5,612) |
2016 (n = 8,298) |
2017 (n = 10,841) |
2018 (n = 15,709) |
2019 (n = 14,644) |
2020 (n = 29,594) |
|---|---|---|---|---|---|---|---|---|---|---|
| PROSPERO | 284 (99) | 759 (99) | 1,525 (99) | 2,707 (100) | 5,600 (100) | 8,279 (100) | 10,822 (100) | 15,663 (100) | 14,569 (99.5) | 29,234 (99) |
| Non-PROSPEROa | 4 (1) | 10 (1) | 9 (1) | 6 (0) | 12 (0) | 19 (0) | 19 (0) | 46 (0) | 75 (0.5) | 360 (1) |
| arXiv | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (0) | 0 (0) | 1 (0) | 0 (0) | 2 (0) | 0 (0) |
| ClinicalTrials.gov | 3 (1) | 9 (1) | 6 (0) | 3 (0) | 5 (0) | 11 (0) | 5 (0) | 11 (0) | 6 (0) | 11 (0) |
| F1000 Research | NA | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 2 (0) | 3 (0) |
| HRB Open Research | NA | NA | NA | NA | NA | NA | NA | 1 (0) | 11 (0) | 12 (0) |
| ICTRP | 1 (0) | 1 (0) | 3 (0) | 1 (0) | 6 (0) | 6 (0) | 8 (0) | 13 (0) | 10 (0) | 44 (0) |
| medRxiv | NA | NA | NA | NA | NA | NA | NA | NA | 7 (0) | 44 (0) |
| OSF Preprints | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (0) | 2 (0) | 18 (0) |
| OSF Registries | NA | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 3 (0) | 5 (0) | 22 (0) | 204 (1) |
| PeerJ Preprints | NA | NA | 0 (0) | 1 (0) | 0 (0) | 1 (0) | 1 (0) | 3 (0) | 0 (0) | NA |
| Protocols.io | NA | NA | NA | 0 (0) | 0 (0) | 0 (0) | 1 (0) | 9 (0) | 5 (0) | 11 (0) |
| PsyArxiv | NA | NA | NA | NA | NA | 0 (0) | 0 (0) | 2 (0) | 3 (0) | 2 (0) |
| SSRN | 0 (0) | 0 (0) | 0 (0) | 1 (0) | 0 (0) | 1 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| SciELO Preprints | NA | NA | NA | NA | NA | NA | NA | 0 (0) | 0 (0) | 4 (0) |
| SocArXiv | NA | NA | NA | NA | NA | NA | 0 (0) | 0 (0) | 0 (0) | 1 (0) |
| SportRxiv | NA | NA | NA | NA | NA | NA | 0 (0) | 0 (0) | 0 (0) | 2 (0) |
| Wellcome Open Research | NA | NA | NA | NA | NA | 0 (0) | 0 (0) | 1 (0) | 5 (0) | 4 (0) |
Abbreviations: PROSPERO = International Prospective Register of Systematic Reviews; HRB = Health Research Board; ICTRP = International Clinical Trials Registry Platform; OSF = Open Science Framework; SSRN = Social Science Research Network; SciELO = Scientific Electronic Library Online; NA = not available
Values are shown as numbers (percentages).
We described “NA” if the platforms did not exist or did not accept registrations throughout the 10-year period.
Creation years of the platforms were as follows: PROSPERO in 2011, arXiv in 1991, ClinicalTrials.gov in 2000, F1000 Research in 2012, HRB Open Research in 2018, ICTRP in 2005, medRxiv in 2019, OSF Preprints in 2007, OSF Registries in 2012, PeerJ Preprints in 2013, Protocols.io in 2014, PsyArXiv in 2016, SSRN in 1994, SciELO Preprints in 2018, SocArXiv in 2017, SportRxiv in 2017, Wellcome Open Research in 2016.
PeerJ Preprints did not accept new registrations since September 2019. We referred to the creation year of PROSPERO in “Booth A, Clarke M, Dooley G, Ghersi D, Moher D, Petticrew M, et al. The nuts and bolts of PROSPERO: an international prospective register of systematic reviews. Syst Rev 2012;1:2. doi:10.1186/2046-4053-1-2.” We referred to the creation year of ClinicalTrials.gov and ICTRP on their official sites. We referred to the creation year of OSF Registries in https://www.cos.io/blog/new-osf-registries-enhancements-improve-efficiency-and-quality-registrations. We referred to the creation year of Protocols.io in “Teytelman L, Stoliartchouk A, Kindler L, Hurwitz BL (2016) Protocols.io: Virtual Communities for Protocol Development and Discussion. PLoS Biol 14(8): e1002538. doi:10.1371/journal.pbio.1002538.” We referred to the creation year of other platforms in “Kirkham JJ, Penfold NC, Murphy F, et al. Systematic examination of preprint platforms for use in the medical and biomedical sciences setting. BMJ Open 2020;10:e041849. doi:10.1136/bmjopen-2020-041849.”
a Non-PROSPERO included 16 preprint platforms.