So far, this course has focused on writing research manuscripts. This week, I'm going to cover other types of writing in science, such as the literature review, grants, and letters of recommendation. Some of these types of writing may be things that you need for your career right now, some of them may be things to put in your repertoire for the future. In this module, I'm going to talk about writing a narrative review article. A review article is a great thing for a graduate student or young investigator to tackle. It's a lot of work, but it gives you a chance to dive into the most recent literature in your field. It also gives you practice on reading papers synthesizing and organizing a large amount of information and of course, writing. Review articles can also help your career. Well-written and well-organized reviews may garner a lot of readers and citations because they are helpful to other scientists. What's the goal of a review article? The idea is to synthesize the recent, primary literature on a topic. There's a huge proliferation of papers these days. Nobody can keep up with the entire primary literature. Your job, as a review article author, is to pull together and summarize the recent primary literature so that somebody can go to your paper and get a good sense of the field. A review article summarizes what we know and what we dont know on a topic. It may also address particular controversies, and in the process of doing a review article, you're also putting together a comprehensive list of citations on a topic or research question, and that can be a great resource for others in the field. Just so you are aware, there are three basic types of review articles. In this module, I am going to address the non-systematic review, also called the narrative review. But I want you to be aware of the other options. A systematic review is a more comprehensive review that uses a rigorous search strategy to try to identify all relevant studies on a particular research question, even possibly unpublished studies. There are also what we call meta-analysis. These are systematic reviews that go one step further, informally pool data across different studies using statistics for data pooling. Again, in this module, I'm just addressing non-systematic reviews as the other two types involves some more technical details, more technical than I want to get into in this module. When writing a narrative review article, you start by searching the literature. You will likely start with a broader search to get a sense of what's out there. But then you are going to need to narrow your focus. Otherwise, there will just be too many papers to read. Your review needs to have a clear thesis or theme. This is the key to a good review article. It can't just be, I'm going to review micro arrays, or I'm going to review breast cancer, those topics are too broad. Instead, you might choose to review the use of microarrays in microbiology, or statistical techniques for microarray data. Or the history of microarray technology. You could do a whole review on the link between breast cancer and exercise or between breast cancer and alcohol. The topic has to be narrow and focused enough to make it tractable. Early in my career, I wrote a literature review on eating disorders in athletes. The body of literature on eating disorders in this specific population was small enough that I was able to cover this literature in a single review. Organization is critical. When we talked about the writing process, I told you about the pre-writing step. For review articles, the importance of pre-writing is magnified. You have to find a way to get organized or you will never finish writing the review. There's just to much information. For my review on eating disorders in athletes, I typed notes from each paper as I read the papers. I also figured out the sections and subsections of the paper, early in the process. So that I could organize my notes, by section and by subsection. There are several computer programs available that can help you to organize your references and notes, such as endnote and Mendely. You can see that the reading, note taking and organization of information is going to take way more time than the actual writing of the review. So focus on that pre-writing step. I recommend writing the article in sections, each with their own headings. That helps to organize the review and also makes life easier for readers. If you have numeric information, maybe put it in a summary table, for example, I used a table in my review to present data about the prevalence of eating disorders in different sports, and for men and women separately. If you have a tangential information, you could put that in sidebars. I had case reports on individual athletes who suffered from eating disorders. These made interesting stories, but that kind of thing can go in a sidebar or box off to the side, if it's hard to integrate it into the text. Finally, write for a broad audience. People may be reading your review article as an introduction to the field. So don't abbreviate too much. And don't assume prior knowledge. And, of course, write in a lively, engaging, and easy to read style, using all the writing tips you've learned in this course. A review article usually starts with an abstract, which I recommend that you write last. You're going to have an introduction section that clearly states the aim of the review. In my article on eating disorders in athletes, I started with some historical papers, I went back to the 1980s, where the first papers on eating disorders in ballet dancers were published. These papers romanticized eating disorders in athletes, so I talked about this as an interesting way to introduce the topic. But then I jumped into my overall theme, which was that eating disorders in athletes need to be considered separately from eating disorders in the general population. The nature of the disease may be fundamentally different in athletes. And then, I clearly stated the goal of my review, which was to critically evaluate the literature in the areas of measurement, prevalence, risk factors, outcomes, diagnosis, prevention, and treatment. The body of the paper should be broken into sections that have a nice logical structure. For my review paper, it was easy because I just divided my sections into definitions and diagnostic criteria, measurement, prevalence, risk factors, etc. And then, I even had subsections within each of those sections with separate subheadings. In each section, I summarized what we know on the topic, what remains unknown, and how studies could do better in the future to fill in the gaps. The conclusion should summarize what you found and give specific recommendations for what researchers should do going forward. In my review, I noted that male athletes are at much higher risk of eating disorders than men in general, but eating disorders in male athletes has been sorely understudied. I also suggested a specific type of study design. That might be able to more accurately identify eating disorders in athletes. So I gave a bunch of very specific recommendations including stating what I thought should be the priorities in research going forward. Then, of course, you have the references, for example, my review had 173 references. Just to give you an example of a theme, or thesis, so the theme of my literature review was that eating disorders in athletes have distinct ideologies and require specialized approaches to things like measurement, diagnosis prevention and treatment. The aims of the literature review, the chapter were to critically review the latest research on eating disorders on athletes including, measurement issues, prevalence, risk factors, sequelae, prevention and treatment strategies. And the sections of my paper lined up exactly with these goals. I had an introduction, and then definitions and diagnostic criteria, then measurement issues, then prevalence, then risk factors, and so on. And I actually had subsections with subheadings, within each of these larger sections. For example, under outcomes, I had distinct subsections on skeletal effects, injuries, detriments to performance, mortality and comorbidities. It was pretty easy to write the review once I had my organizational structure in place. Because each of the subsections had, maybe one to ten relevant papers that needed to be synthesized. So again, the key to review articles is narrowly and clearly defining the theme of your review and then collecting, reading and organizing your papers in an efficient manner, and then coming up with a good, logical organizational structure. If you can do all that, then writing the review is much easier. Here are some other examples of reviews. Here, I'm quoting a review on CRISPR-Cas9 genome editing. CRISPR-Cas9 is a huge topic, but the authors didn't try to review everything about CRISPR-Cas9, rather they narrowed in on the history of the technology, so this review was focused on history. Here were the sections of that paper. If you skim through them, you'll see that they give an introduction to the technology, and then they go back decades in history. Then, they talk about figuring out the biological mechanism of how CRISPR-Cas9 actually works. Then, they go into the more recent developments in the technology, and they give some clues about where we're going, and what the technology might be used for in the future. Here's another example, Ebola has been written about a lot lately due to the big outbreak in West Africa that occurred in 2014. This review that I'm quoting here looked specifically at one controversial aspect of Ebola, which is how long does the virus persist and shed after someone has recovered from Ebola and isn't sick anymore. That was a major concern especially at the end of the outbreak because doctors were worried about new cases cropping up and rekindling the epidemic. Here are the sections of that paper, they briefly describe their search strategy that's not essential in a narrative review, but something you could include. Then, they reviewed studies that have measured shedding in blood and body fluids. Then, they reviewed all the studies that have tried to define the risks of transmission from various modes. Such as sexual transmission and mother to child transmission. Then, they gave a conclusion with take home messages, like one of the take home messages was that although there are documented cases of sexual transmission from survivors, the risk is pretty low. And another take home message was, we just don't know about things like transmission through saliva or tears of survivors. So more research would be needed on those areas.