Article Text

Download PDFPDF

Delays in publishing systematic review registrations in PROSPERO are hindering transparency and may lead to research waste
  1. Livia Puljak
  1. Catholic University of Croatia, Zagreb 10000, Croatia
  1. Correspondence to Dr Livia Puljak, Center for Evidence-Based Medicine and Health Care, Catholic University of Croatia, Zagreb 10000, Croatia; livia.puljak{at}; liviapuljak{at}

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

PROSPERO is an international prospective registry of systematic reviews.1 Registering a systematic review prospectively is considered a good research practice for multiple reasons, including transparency of the planned methods and prevention of unnecessary duplication of effort. Solla et al 2 recently reported concerns that PROSPERO registration may not prevent double review on the same topic because the PROSPERO search engine is apparently failing in finding similar review projects.

Another pertinent current problem of PROSPERO may hinder intended transparency and promote research waste and duplication efforts, namely, major delays in checking and publishing registrations that the PROSPERO is experiencing.1 On the PROSPERO web site, it has been indicated since 2019 that they are receiving an unprecedented number of records and that thus registrations from UK are prioritised, as the PROSPERO is funded by UK.1 A recent systematic review registration submitted by our team is a telling example of the extent of the delay—we submitted the registration on 24 September 2019 and PROSPERO registered it 6 months later—on 26 March 2020.3 Initially, in the public record of this registration, there was no date of submission—only ‘Date of registration in PROSPERO’. In May 2020, the PROSPERO started publishing the ‘Date of first submission’, which is commendable because this enables full transparency about the registration timeline. Furthermore, it provides basic information that may be used in methodological studies about PROSPERO,4 which analyse systematic review timelines.

However, if someone searched PROSPERO during those 6 months, even with the less-than-perfect search function, they would not know about pending registration of our review.

To rectify these major delays, currently (June 2020) the PROSPERO informs authors that ‘during the pandemic’, all submissions waiting to be registered for more than 30 days, and which passed a basic automated check, will be published automatically.1 However, even if a registration is published automatically after 30 days, this is still 30 days during which the public is unaware of this pending registration. Furthermore, the PROSPERO indicated that this mode of publication is enabled during the pandemic, indicating that this may be temporary and that potentially, PROSPERO may be back to major publication delays when the COVID-19 pandemic subsides.

Thus, it would be optimal if PROSPERO would publish all submissions immediately following the basic automated check, without any delay. Such approach would have high potential to reduce research waste and duplication of effort.

Ethics statements

Patient consent for publication



  • Contributors LP designed and wrote the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; internally peer reviewed.