Types of Scientific Literature

While the research article is the workhorse of the scientific literature, it is by no means the only game in town.  Presented below, in no particular order, is a brief list of some of the various types of written information that scientists may consult during the course of their work.  For a brief introduction to the peer review process and primary research articles, see my Very Brief Introduction to the Scientific Literature.

• Primary research articles (aka “original research articles” or just “research articles”) – These are your standard scientific articles.  Most often published in peer reviewed journals, primary research articles report on the findings of a scientists work.  They will almost always include a description of how the research was done and what the results mean.  Joe Dunckley over at the blog Journalology, has a nice series of posts about what the scientific paper is and what may be wrong with the current model.
• Review articles – These can be easily confused with primary research articles.  They are also published in peer reviewed journals, but seek to synthesize and summarize the work of a particular sub-field, rather than report on new results.  Review articles will often lack a “Materials and Methods” section.  Students who are asked to use only primary research articles for their projects can still find review articles useful – they can provide background information and their Works Cited sections can contain a wealth of useful references.  I have briefly summarized the difference between primary research articles and review articles in my Very Brief Introduction to the Scientific Literature.
• Editorials/Opinion/Commentary/Perspectives – An article expressing the authors view about a particular issue.  This may be an issue of science policy (“The NSF needs to…”) or urging a particular research agenda (“More scientists need to study X…”) or even taking a side in a particular scientific dispute (“These folks are right, the other folks are wrong”).  These articles can be well researched and include a lot of citations to the peer reviewed literature, or simple items without citations.  They can appear in peer reviewed journals, in trade publications, or in popular publications (although the items that appear in trade or popular publications are often easier for students to recognize as not-primary research articles.)
• Trade publication articles – Between the standard scholarly journals (Nature, Journal of the American Chemical Society) and the popular publications (Time, Newsweek, Scientific American) lie the Trade publications.  These publications are often aimed at medical professionals (Vaccine Weekly) or particular disciplines (Chemical and Engineering News).  Articles in these publications may be several pages long and include a few references, but they are usually summarizing research published in other publications or reporting on industry news.  These can be helpful for keeping up with your discipline or finding a research topic.
• News – Science news articles can be found in a wide variety of publications.  Popular newspapers and magazines, trade publications and scholarly publications can all have science news articles.  These articles often will refer to a recent study published as a primary research article.
• Blog posts – The world of scholarly publication is changing, although no one is quite sure what it is evolving into.  We do know that scientists are blogging about all kinds of things: their daily research, science policy or life in academia.  Blogs can be a great way to get involved in the scientific community, and many scientific blog posts can point you back to the peer reviewed literature.  How blogs will be valued as a means for communicating research findings is still in question.  While some scholars continue to dismiss blogs as a scholarly medium, other have embraced their potential for communicating science quickly and effectively.
• Article comments (formal, reviewed) – Traditionally, if you had a criticism of a published journal article, you submitted a formal comment.  These short pieces would be reviewed by editors or possibly peer-reviewers, and published in a subsequent journal issue.  In the print world, it was practically impossible to know what articles had been commented on or where to find the comments.  Now that almost every journal is online, a link to a formal comment is often included on the site for the original article.  Of course, the formal nature of these comment could often be frustrated, and certainly didn’t encourage rapid communication (See this great piece about the difficulty of getting a comment published.)
• Article comments (online, with or without moderation) – Since one of the problems with formal article comments is slow turn around time, many online journal systems have the ability to allow users to comment directly on the articles.  Sometimes these comments are moderated, sometimes they aren’t.  Interestingly, many online journal articles have not seen a large amount of comments, but blog posts about those articles can have comments.
• Technical Reports – Government agencies and NGO’s often do scientific work.  The reports they produce are not often peer reviewed, but can be an important part of the scientific literature.  Reports from the World Health Organization or the USGS can provide vital information to scientists.  These reports can be found in scholarly databases and on the web, and are classified by some folks as gray Literature (see below).
• Pre-print/Post-print – A pre-print is simply a journal article in it’s original form, before it is peer reviewed or typeset by a journal.  A post-print refers to the same article after peer review but before typesetting.  I’ve heard the term pre-print applied to both.  Sometimes, these pre-prints can be posted online to a scientist’s website or some kind of a larger repository (the most famous of which is arXiv.org, a repository for physics, math, computer science and other related disciplines).  Hopefully, the journals these articles have been submitted to legally allow the author to post the aritcle to such a website in their “copyright transfer agreement.”  Posting these materials online is part of “green” open access.  This can be a great source of journal articles that your institution doesn’t subscribe to.  Often considered gray literature (see below)
• Field Trip guides – More common in geology than in other scientific disciplines, these guides are often considered a part of the gray literature.  They may be produced locally or published more widely.  Field trips are often a major part of large and small conferences.
• Other gray literature – The term “gray literature” largely refers to items that are distributed or published outside of the traditional journal and book publishers.  It typically referred to items that could be difficult to find, although I believe this distinction is becoming less important as these items are now often discoverable in internet search engines.
• Maps – Thematic maps can be an important part of many scientific disciplines.  They can be published as stand alone publications, supplements to journal articles or books, or parts of technical reports from government agencies or NGO’s.  Scientific thematic maps often include several pages of prose describing the methods used to create the maps, the data that inform the results, and the interpretations that result from the data.
• Conference proceedings – long papers – Other than journal articles (and the related bits) conferences are the second major form of formal communication among scientists.  A group of scientists gather to present findings about their research and gossip about their graduate school friends.  Some conferences have very broad topics (like the American Association for the Advancement of Science annual meeting) and some can be very specific (like the conference on Optics and Photonics for Counterterrorism and Crime Fighting).  At these conferences scientists may stand up at the front of the room and give a PowerPoint presentation.  Or they may stand in front of a 3 foot by 6 foot poster describing their work.  Sometimes, they will write up a formal paper explaining the same thing they did at the conference in a bit more detail.  These papers can be published in book form in a volume referred to as the “Proceedings of Conference X.”  Sometimes these papers will go through peer review, and sometimes they won’t.
• Conference proceedings – abstracts – More often, the research presented as posters or PowerPoint presentations at a conference won’t have a formal write up published after the fact.  Occasionally the scientists will archive a copy of their presentation on a website, but most often the only record of the presentation will be the brief description (abstract) of their presentation that the scientists submitted to the conference organizers.   These abstracts can be found in search engines and scholarly databases, and students often want to find the paper that the abstract describes, only to learn that there isn’t a paper.  This can be frustrating.
• Books (including reference materials like handbooks and dictionaries) – You’ve seen these before.  They still exist, in your library or your library’s off site storage facility. Most scientific books cannot be considered ‘primary research’.  In general, they describe and interpret the primary research published in the journal articles.  Of course, more and more you can find full text versions of books available via publishers websites, Google Books or the Hathi Trust, sometimes free, sometimes for a fee.
• Book series (sometimes called “Special Papers”) – These can be confusing.  In some fields, these book series publish individual chapters that could be considered primary research articles.  These individual chapters are cited and indexed individually, which can occasionally be confusing for students trying to find them.  In addition, these items can sometimes look a lot like journals – they may have volume numbers and a series title that looks like a journal title.
• Dissertations/Thesis – These are the final products that result from research conducted for a PhD or a Masters degree.  These items can often be very long, going into great detail about methods and with lots of appendices of data.  The literature review sections can also be exhaustive. Thesis and dissertations have become easier to find in recent years as many libraries post complete copies of completed dissertations online.  This can be useful, because libraries have been reluctant to lend copies through ILL. Dissertations or thesis are often cited later on by their authors in future journal articles.  While they undergo exhaustive review by academic advisers and committee members, they wouldn’t be considered “peer-reviewed”.