I think that it doesn't really matter where you publish, assuming that there are registers other than PROSPERO where you can do so without specific affiliation credentials. If I'm not mistaken, even Cochrane review protocols are registered in PROSPERO. You can even opt to publish the protocol in journals such as BMJ Open.

What matters is that there is a freely-available way for people to check your protocol vis-a-vis your final systematic review publication for adherence and/or deviation issues (and for deviations, an explicit attempt to explain them in the final report). At the end of the day, you'll link the online source of the protocol to your final systematic review publication anyway. Good luck!

Hi. See the link below that might help:

https://libguides.newcastle.edu.au/sysreviews/protocols

For protochol exchange purpose Research Square is excellent - https://www.researchsquare.com/browse?journal=protocol-exchange

Thank you so much for your answers !

For systematic reviews, Publish preferably in PROSPERO or Cochrane (only if you are working specifically on a cochrane review).There are other registeries of Joanna Brigg's Institute, but for registration of systematic reviews, PROSPERO is more widely used.

Also, for scoping reviews, since PROSPERO is not registering scoping review at the moment, you may register scoping review in OSF (open science framework).

Ii think peospero publushing style is more preferable for systemetic review reseadch

I would suggest prospero and protocol exchange as the most popular ones for protocol registration. With prospero, it takes a few months for registering the protocol so I would recommend plan ahead and submit it well in advance.

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018113051

PROSPERO for systematic reviews, but for other types that PROSPERO does not register, you can also use OpenScienceFoundation Registries https://osf.io/registries

I think PROSPERO is a standard option, however if you want to go beyond this you can actually find a journal that will publish the protocol. This is a more rigorous approach but allows you to justify several of your methods in advance, and enables you to refer back to the publication more easily later on. Several journals allow protocols, one I worked with was BMJ Open. You can check the journals' websites, prior publications, or email the journal staff to see if they allow protocols, if it is unclear. If you are not in a rush to complete the review, this is a nice option and the added feedback from peer review of the protocol can be helpful before you start.