I’m still in the process of working on my next blog entry for my series A Crash Course In Tissue Engineering, and I have also been working with Mr. Jordan Arel on doing a podcast (we have received many of your questions and we are doing our best to try and work as many of those in). I am however taking a short break from those two projects to discuss something different but still immensely important: peer review. Peer review is a lengthy and exhaustive process that scholarly work undergoes prior to publication. While peer review is relevant to all areas of scholarly and academic research, it is critically important for biomedical research. It is because of this process that a researcher like myself, who reads at minimum 30 pieces of published scientific literature a week, can have faith that what they’re reading is credible; especially if one wants to reference data or utilize a method for one's own research. Peer review is central to ensuring high-quality scientific work is published.
For those who don’t know, my background is in Biomedical Engineering. I’m currently working on a Masters of Chemical Engineering (with a Biomed focus). I have previously worked in a lab that was focused on polymeric biomaterials, with special attention to both synthetic and natural hydrogels for drug delivery and tissue engineering purposes. I currently work in a slightly more traditional tissue engineering lab, which is focused on myocardial repair and regeneration, but we also collaborate heavily with a Medical Imaging group that studies MRI, and a surgical team at The University of Chicago. In short, I have a bit of experience with the peer review process from projects I’ve been involved in. My goal for this blog post is to discuss what is the peer review process, why is it necessary, and what expectations should one have when submitting a manuscript for peer review and publishing. A small disclaimer: there are a countless number of scholarly journals out there, and all do not operate the same. There are different models that journals adhere to, so I want this to be fairly generalized, but I will refer to the prestigious journal Biomaterials, due to it being an extremely important source in my field. Below is a very generalized flowchart of the peer review process:
Fig. 1: Peer Review Process at Elsevier 
When an author submits a manuscript to a journal, typically the first screening is performed by the Editor-in-Chief. They will subject it to evaluation before it can even be considered for peer review. They look at superficial qualities to see if the content of the manuscript falls within the scope of the journal, whether the basic science was implemented, and if citations are used properly. The Editor-in-Chief needs to decide whether the paper is high enough quality to publish. This decision is based on a couple of factors. Is this paper going to be relevant, interesting, or of use to the subscribers and readers? If not, then the journal doesn’t have much use. The other big factor to consider is how does the paper match up against others that are similar? Depending on the popularity of an area of study, a journal may receive a high volume of manuscripts detailing the same subject, with minor differences. Former Editor-in-Chief of Biomaterials and an idol of mine, David F. Williams, has discussed the struggles regarding this :
“This decision is never an easy one and the Editor takes into account the added value of the paper in comparison to other papers being published in Biomaterials in that specific area. Thus, a manuscript dealing with a slightly different way of sintering hydroxyapatite, or delivering a well-known drug in a slightly different manner, might be difficult to accept in view of the large number of papers on those subjects published recently. Approximately 35% of manuscripts are rejected on this basis...”
The Editor-in-Chief has a great deal of power over what even makes it into peer review, let alone all the way to getting published. If the manuscript fails the first screening, it is returned to the author along with a letter with an explanation. If the manuscript passes the first screening, it enters the peer review process. From here, the Editor-in-Chief contacts appropriate external reviewers or referees, and invites them to review the manuscript. Reviewers are typically well established experts. If they accept the invitation, they will review the manuscript and write an assessment. There is usually more than one reviewer at this stage. Their job is essentially to find issues with the paper or the researcher’s methodology, and to further gauge the quality of work.
There are different types of peer review processes, with the most common being single-blind review. This type is quite common, where the author does not know who is assessing their manuscript, however the reviewers will know who the author is. The next type is double-blind review, where both the author and the reviewers are anonymous. The final type is open review, where all parties are known to one another. There is debate about which is the best type, but each does have its own pros and cons.
When the reviewers are finished, the assessments are sent back to the Editor-in-Chief, where they will read the assessment and re-read the manuscript. If the first set of reviewers gave a bad assessment of the manuscript, sometimes it can be sent to another reviewer for a follow-up assessment. There can also be another reviewer who only assesses grammar, punctuation, and other English/language components, although this isn’t always the case. In the end, once the Editor-in-Chief has received all of the assessments, they have several choices: they can reject the manuscript all together, accept the manuscript just as it is, or they can request that the author revise the manuscript and resubmit within a short period of time set by the Editor-in-Chief. According to David F. Williams from Biomaterials, a further 40% of manuscripts are rejected at this point. The author will revise the manuscript with the aid of the reviewer’s assessments. After revising, the manuscript is resubmitted, and it goes through the same process as before; being placed back under intense scrutiny by the previous reviewers. Once finished, the reviewers send their assessments back to the Editor-in-Chief, who makes the final decision whether or not to publish. In the journal Biomaterials, 75-80% of all manuscripts are rejected, and 95% of the manuscripts that are published undergo revision . If the manuscript is accepted for publication, an Editorial Board decides what issue it should be published in, and eventually it makes it online or in print.
Peer review is a long process that can take many months to run its course; assuming one manages to avoid rejection. When reviewers are assessing a manuscript, their job is to essentially tear apart your submitted work. They analyze methodology, results, and discussion, and try to find problems or weak spots. Papers can be rejected due to flaws in methodology or the way the author analyzes results, or makes conclusions about the findings that don’t seem to hold water, but it’s due to this intense scrutiny that only the highest quality research will be published; this is why rejection rates are so high among what are referred to as “top” journals like Science, Nature, Cell, etc. They want cutting edge research, but couple that with an extremely rigorous peer review process. But many of the articles that are published become cited heavily, suggesting they have amazing importance (but the journals are also very well known which I will admit does help).
Peer review and publication have two main purposes: it serves as a channel to validate one’s hard work. Having others in the field, your peers, evaluate your work and potentially tell you that it is worth something by effectively recommending it for publication for the world to see. But more importantly, it serves as a regulating force. Peer review is where the rubber meets the road; airtight science and methodology will likely survive peer review, whereas sloppy or poorly done science will most likely never see the light of day. Peer review allows one to be able to evaluate the validity of claims. There has been a huge rise in what I will simply call “alternative science.” Essentially pseudoscientific claims (typically surrounding health and diet) that are spread through blogs and social media, usually with no backing evidence. These claims typically come from sketchy sources, who did not subject their research or evidence to the peer review process, and therefore really shouldn’t be taken seriously. Bottom line is that having your research survive peer review and make its way to publication means you have validity.
When submitting work for peer review and publication, it’s not a process that one should expect to be over quickly. In my experience, it can feel like an absolutely merciless academic gauntlet, and it’s the real reason why they say you need to have thick skin to survive in research. People will pour their heart and soul into a project for a year, only to have some guy they’ve never met metaphorically shred their work; this happens not only to graduate students but also to seasoned professors and professionals. But, it’s necessary to maintain the integrity of scholarly research.
Thanks for reading everyone. I will hopefully get back on track with Jordan and the podcast, and I hope to have the first real blog entry done soon as well.
 Peer Review Process, Elsevier, n.d. https://www.elsevier.com/__data/assets/image/0007/90079/Rev_process.png.
 D.F. Williams, P. O'Donnell, Writing Papers for Biomaterials, Elsevier. (n.d.). http://cdn.elsevier.com/promis_misc/writing_papers_biomaterials.pdf.