Conducting a Literature Search: How Much Should You Read as a Researcher?

Importance of an effective literature search

Research is never done in a vacuum – it is built on previous knowledge in the field and aims to add to the information available in a specific subject area. Hence, conducting a literature search is essential to find potential gaps in knowledge that you can then address through your research study.

The first step toward productive research is selecting the topic based on an effective literature search, which requires authors to read extensively and cover all aspects of relevant research in their field. Conducting a literature search is not a one-time thing either; it’s an ongoing process for authors looking to stay updated on developments pertaining to their study, identify gaps in existing as well as in their own research, and plan for further studies. Research based on exhaustive and effective literature search can also help other academics reading your paper identify potential research avenues going forward.

Is there a threshold for reading research literature?¹

While conducting a literature search, researchers may often encounter a potential hurdle in deciding how much to read. According to an article published in Nature, the number of scientific papers published has increased by 8-9% annually over the past several decades.² In the biomedical field alone, about 1 million research papers are added to the PubMed database every year.² The National Center for Science and Engineering Statistics reports that from 2008 to 2018 the global science and engineering publication output increased from 1.8 million to 2.6 million articles.³ Considering this data it’s easy to see how researchers may feel overwhelmed; the information overload could also make it difficult for them to define a threshold for reading research literature.

According to a study, the average number of references to be included in a research paper is 45 and 90% of the research papers studied cite between 8 and 102 references.⁴ While some journals limit the number of references (Nature, for instance, has a restriction of 50 references per paper), many others do not have any curbs on the number of sources cited in a paper. While there’s no strict or definite number of articles that should be read when conducting a literature search, the entire exercise of reading research literature should be timeboxed and planned based on the subject, how well researched it is, and the study type.

Listed below are a few tips when conducting literature search that could help optimize the quantity and quality of your reading and ensure that reading research literature is as less effort intensive as possible: ⁵

1. Browse open access (OA) content
   1. The content of OA journals can be read, downloaded, and distributed freely, unlike traditional journals that may require paid subscriptions.
   2. Some well-known OA databases and directories include the Directory of Open Access Journals, PubMed Central, Public Library of Science, arXiv (a depository for the sciences, maintained by Cornell University), bioRxiv (for articles in biology and medicine), ROAD (to find OA journals by country or subject), etc.
2. Search on Scopus, an Elsevier-owned database. It helps find relevant research and provides access to metrics and data.
3. Use aggregator sites such as Feedly to follow custom RSS feeds such as those of PubMed
4. Use academic search engines for specific searches such as for keywords, authors, niche subjects, etc.—Google Scholar, ERIC (Education Resources Information Center), RefSeek, JURN, etc.
5. Simplify the entire process by downloading , an effective literature search app that lets you set up a personalized reading feed based on your topic of interest. It even recommends new articles in your area of research, ensuring you’re always updated on important research.

Tips for conducting an effective literature search

Here are a few important tips that could help you stay focused and efficient while conducting a literature search: ⁶

1. Finalize a broad subject and then work toward the specifics to narrow down the search
2. Ensure that you know your target audience—researchers, students, business professionals, or all of them?
3. Although most content is now available online, brick-and-mortar libraries can also be a good source for accessing articles from journals that require paid/institutional membership.
4. Create an exhaustive initial list of sources because eventually only few would be finalized for inclusion in the paper.
5. Initially, a good option would be to skim through abstracts/key points, visual abstracts, or even listen to audio summaries of articles (if available) for a quick shortlisting decision based on the suitability of the topic, and then move ahead to read the complete documents.
6. Note down any questions that you may have while reading previous research literature, such as gaps in existing studies, possible alternate methods for solving a problem, etc. These questions could serve as starting points to steer your research in different directions.
7. Collaborate with fellow researchers to divide research tasks while scouting for appropriate journals and articles.
8. Dedicate only a few hours per day for reading to ensure that the process does not become overwhelming.

We hope that the tips and sources discussed in this article would help you when conducting a literature search and help you set a threshold when it comes to reading research literature.

References

1. Grewal A. et al. Literature search for research planning and identification of research problem. Indian J Anaesth. 60(9):635-639 (2016). doi:10.4103/0019-5049.190618. PMID:27729689
2. E. Scientific literature: Information overload. Nature 535:457-458 (2016). doi:10.1038/nj7612-457a
3. White K. Publications output: US trends and international comparisons. National Science Foundation. https://ncses.nsf.gov/pubs/nsb20206/. Published December 17, 2019. Last accessed August 29, 2022.
4. Choueiry G. How many references should a research paper have? Study of 96,685 articles. Quantifying Health website. https://quantifyinghealth.com/how-many-references-to-use-for-research-papers/. Last accessed August 29, 2022.
5. MCPHS University research guide. Finding open access content. https://mcphs.libguides.com/open_access/finding. Last accessed August 27, 2022.
6. #GradHacks: A guide to reading research papers. https://www.scientifica.uk.com/neurowire/gradhacks-a-guide-to-reading-research-papers. Last accessed August 28, 2022.