Hi Ken,

I have registered systematic literature review protocols on PROSPERO previously. I find this a very useful database for the following reasons:

1. In planning to undertake a systematic literature review, the main motivation would be to compile and critique evidence on a specific research question. Usually a pragmatic search would highlight whether or not a systematic literature review in this area has been undertaken. However, given the upsurge in research teams conducting systematic literature reviews and the time commitment to undertake these robustly, there was always the possibility that some other team were conducting the same review and may have it published before your team completed it. This may then make all your hard work obsolete. More and more research teams now check PROSPERO before commencing a review in case another team is working on the same question.

2. The fields PROSPERO require when you register your protocol can be helpful to adopt as a framework for developing your review strategy. You can also learn from other researchers on how they approached research questions in similar clinical areas.

3. It is also possible to develop research collaborations with active researchers who are interested in the same research area.

I am not able to advise whether this will become a requirement by journals to publish the actual review when completed. However, in my experience some reviews don't make it to the publication stage due to limitations on the evidence, value to the academic community or other technical issues. However, a body of evidence was generated in the process of the review which can be helpful to other researchers and PROSPERO affords researchers an extra outlet to identify this work.

I hope this is helpful.

I agree with Rachel.

My team haven't registered in PROSPERO, but it's a great way to document a plan, and pre-define exactly what you are assessing in the systematic review.

This is a way to show journals how authentic your work is and how did you stick to a published plan. And most importantly, this prevents reporting bias, because you have to report all outcomes that you defined in the protocol. However many people publish without registering, but I personally think it's better to submit a protocol to PROSPERO before doing the review.

Though the registration of systematic review is not mandatory, but it is a good practice to register the systematic review/meta-analysis (if they qualify for registration). Other than PROSPERO, the systematic review protocol can be registered in the Open Science Framework or Figshare. You can also publish the protocol of your systematic review in the journal.

There are certain benefits of registration:

• The registration of systematic review is used as a guide to carry out the review because it describes the rationale, hypothesis, and planned methodology of the review.

• It helps to avoid the duplication of reviews so that the same review is not undertaken again by another person. Therefore, it is required to check-in PROSPERO before initiating any systematic review to ensure that it is not already done.

• The registration of systematic reviews promotes transparency and assists in identifying the biases (outcome reporting or selective reporting biases). If the review is registered or its protocol is published, then it means there is a record of key elements of planned review including inclusion and exclusion criteria and intended outcomes. Then after the publication of the review, one can compare it with its protocol or PROSPERO registration to identify the discrepancies. Much work has been done on using the review protocols or PROSPERO registrations where researchers compare them with their corresponding published reviews to identify the outcome reporting or selective reporting bias.

It means that PROSPERO is not just a simple database and it has many benefits as discussed above. As I said, the registration of the review is a good practice, but it is not followed strictly. Also, it depends whether the registration of review or meta-analysis is a mandatory requirement of any journal for its publication. However, I would recommend the registration and publication of the protocol. Read this article to understand why it is important to register systematic reviews: Why prospective registration of systematic reviews makes sense

https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/2046-4053-1-7

Thank you so much Richeal, Sebawe, and Rabia, for taking valuable time out to answer my question. All of you have really written very clear answers and in summary I will recommend to my Postgraduates to register in PROSPERO because of the advantages that you mention.

Richeal, its a small world!! To think that of all the researchers in the world who could have contacted me a person who works with me would know the answer to this is fascinating. Thank you so much, and we really need to sit down and work out how best to build our research groups in IT Sligo. Your answer was excellent.

Sebawe, thank you as well for contributing with useful further information to back up Richeal, and good luck with your medical studies in Jordan? In what area of medicine are you thinking of specialising?

Rabia, that was also a fantastic reply to my question and thank you so much for sending on the link to the paper. I have asked all my Postgraduates to read it!! Good luck with your Postdoc in Sydney and please contact me if you are ever looking for further research work in Ireland. There may be opportunities in our College in the future.

Thanks Ken