September 29, 2017: Preprints: What, Why Not, and How


Harlan M. Krumholz, MD
Harold H. Hines, Jr. Professor of Medicine
Yale University School of Medicine
Director, Center for Outcomes Research and Evaluation
Yale-New Haven Health System
Founder, Hugo


Preprints: What, Why Not, and How


Pragmatic clinical trial; Clinical research; Yale; Preprints; YODA; Peer Review

Key Points

  • The goal of preprint servers is the easy and rapid sharing of information with other scientists. They have the potential to enhance collaboration, reduce waste, and increase transparency.
  • Preprint servers are meant to complement, not replace, peer-reviewed journals.
  • Only 29% of clinical trials results are reported within 2 years of completion, so it is critical to establish a global norm for reporting timeframes.
  • Reporting biases exist, favoring the publication of clinical trials results with positive outcomes.
  • Yale’s YODA Project created MedArXiv as a preprint service, aimed to co-exist with peer-reviewed journals, for researchers to share and receive feedback on their work.

Discussion Themes

Researchers are in a race to help people, and preprints can create a dialogue and opportunity for community feedback long before a journal would publish a paper.

One challenge to preprint servers is the existing business model for traditional journal publishing. A suggestion would be branded preprint servers hosted by these journals, keeping in mind sustainability.

There has to be some screening process for content posted to servers, but sharing results via preprints is not much different than sharing through a presentation at a scientific conference. 

The preprint process helps to eliminate researchers’ fears of being undermined or having someone else publish results sooner simply because of the speed of a particular peer-reviewed journal.

For More Information

To learn more about Yale’s work in preprints, visit or follow @hmkyale on Twitter #pctGR


@Collaboratory1, @hmkyale, @YaleMed, @YODAProject, #Preprints, #clinicalresearch, #PragmaticTrials, #pctGR