How to do a Literature Review for Investigator Initiated Trials

Whether you’re planning to write a publication on your investigator-initiated trial (IIT) or a review paper, the first step is to perform a literature review. At first, attempting to navigate through the vast ocean of knowledge can seem quite intimidating. Where do you even begin? What information do you need to collect? In this article, we’ll describe some of the key steps that will help you efficiently tackle this process.

Define the Scope of your Topic

Before starting a literature review, you first need to clearly define its purpose and scope. After all, you don’t want (or need) to know everything about the field. A lot of people will often skim over this step and begin gathering as much information as possible. However, more often than not, they’ll find out later that they have collected either too much information or that the information is not relevant. In either case, it’s not the best use of your time.

To help you outline the scope, create a list of specific questions you want to be answered through the review process. For example, let’s imagine you are interested in reviewing the current state for dry eye treatments. The following are some example questions you could ask:

  • What are the symptoms of dry eye? What are the causes of dry eye?
  • What are the main types of treatment for dry eyes on the market? How effective are they?
  • What are experimental treatments are in development? What are some associated side effects with these treatments?

Structure your Review

Once you’ve determined the set of questions that you would like answered, the next step is to create a framework for your literature research. The topics and subtopics of your review should answer the questions you’ve outlined in the previous step. At this point, it’s a good idea to also arrange your topics and subtopics to create a compelling story. A good literature review is not just a summary of the literature but also your take on the current state of knowledge. In other words, you should be able to synthesize your own hypothesis and conclusions after reviewing the literature.

Define your Methods

The next step in the review process is to define your search criteria. For instance, how will you search for the information and which types of sources will you use in your literature review? Here are some important aspects to consider:

  • What type of search engine will you use (i.e. PubMed, Scopus, Web of Science, Google, Google Scholar)?
  • Are you only looking for peer-reviewed publications, or will you also include other online sources?
  • Are you looking at just manuscripts, or also abstracts, conference posters, market reports, newspapers and magazines?
  • Are you including a patent search as part of your literature review?
  • Are you only interested in recent publications or also older publications? What is your cut-off requirement for the publication year?
  • Does the impact factor of journals for publications matter in your review?
  • What keywords will you use in your search?

You should be able to access peer-reviewed publications through your institutions’ web portal. However, in some cases, your institution may not have a subscription to the journal of interest. In these situations, you can also use Sci-Hub to retrieve a PDF copy of the papers. At this stage, it’s also a good idea to decide on a reference managing software (such as Mendeley or Endnote) that you’d like to use to keep track of your citations and references. You definitely do not want to be keeping track of them by hand! We’ll discuss reference managing software in a future article.

Search Criteria       

Now that you have a game plan, it’s finally time to start doing the actual research. In your search browser, enter various combinations of the keywords that you’ve selected in the previous steps to generate a list of relevant publications. Ideally, for most literature reviews, you want to have between 10-30 publications. If you have too many or too few publications, then narrow down or expand your search criteria as needed.

Select and Narrow your Search Results

Once you’ve identified the list of publications that you’d like to use, the next step is to retrieve and rank them based on their relevance, date, and impact factor. You want to filter the list of publications you have gathered by selecting only a maximum of 10 key sources to start your review process. Remember that quality is much more important than quantity at this point, and you can always add more sources later if needed. A good starting point for a literature review is other recent review papers on the same topic.

Summarize Key Pieces of Information

As you’re reviewing your list of publications, note the information in a summary table. A good summary table should contain the authors’ names, key results and conclusions, and the paper citation. This table will make it a lot easier for you to gather and arrange data during the review process. When you’re reviewing papers, scan the abstract, figures and tables, and the discussion section for key pieces of information.

Let the Writing Begin

The literature review process is an important first step to writing any type of academic publication. Before you start the actual writing process, decide where you want to publish your work. Each journal will have its own requirements for publication, such as formatting style, length, and the maximum number of citations. Yes, you can definitely have too many sources! We’ll cover the writing of a publication in more detail in later articles. If you need more help with your literature review process or any help regarding your study, please contact Sengi.