Release Date: September 4, 2017
Category: Scientific Writing
Author: Katherine S., Ph.D., E.L.S.
On to Google!
Sorry, no. Google isn’t going to cut it.
Nope. The purpose of a systematic review is to find ALL the relevant papers. You need comprehensive literature databases. For health-related topics, this means Medline/PubMed and EMBASE. There are also more specific databases, such as PsycINFO for psychology research, AIDSInfo for HIV research, or AGELINE for research on elderly patients. You can also look through clinical trial registries, such as the World Health Organization’s International Clinical Trials Registry Platform (ICTRP) Search Portal. There is also “grey literature,” which is literature that isn’t published commercially like technical reports, conference proceedings, and theses. The New York Academy of Medicine curates a database of these publications. There is a fairly comprehensive list of potential databases in the “Literature Searching for EBP Systematic Reviews” document from the Alberta Research Centre for Child Health Evidence. I also suggest looking through the references of the papers you find to make sure you don’t miss anything.
Okay, so I just go to the database link, copy and paste my aim into the search bar, and see what comes up?
You can certainly try that but I don’t think you are going to get very far. A lot of these databases are indexed using Medical Subject Headings (MeSH) search terms. MeSH terms are essentially the dictionary for medical research. They are the vocabulary of your search. You will want to identify the MeSH terms associated with all the individual parts of your aim. From there, you can string your MeSH terms together using Boolean logic (i.e., AND, OR, and NOT). For example, your aim is to evaluate if treatment P improves disease-free survival and the ability to perform tasks R and S compared with placebo in patients with condition X, and one of your inclusion criteria is to only include prospective randomized controlled trials (RCTs). Therefore, you could use the following query: “P” AND “condition X” AND “disease-free survival” AND “randomized controlled trial” OR “RCT.” There are lots of tricks to refine your search. One excellent tutorial for putting together your search terms can be found at the University of California Davis Library website.
I think I’m starting to hyperventilate over here.
Deep breaths. If you are getting a bit overwhelmed at the thought of putting together a search, you can always get some help. Have you talked to your friendly librarian lately?
Google can talk?
Not Google, your librarian, i.e., the person that sits in the room full of paper books and journals that you ignore in favor of downloading pdfs online.
People still do that?
Yes, they do. Librarians are also highly trained at putting together good searches. If your local University librarian doesn’t feel comfortable helping you, odds are good that they know a research librarian who can. A well-designed search can save you a lot of time down the road. It is definitely worth the time and effort to find someone who can help.
Okay, I’ve asked around and found a research librarian. We put together a set of search terms that should catch everything.
Great. Let’s run that through the databases. How does it look now?
Whoa! It came back with 383 articles. That is still a ton of articles.
I know it seems like a lot of articles right now, but that is an excellent starting place to begin screening articles to include in your systematic review. It is better to find extra papers and exclude them than miss important papers.
Now that you have assembled your articles, it’s time to start screening and analyzing them. We’ll get into that in our next article, “Writing a Systematic Review Part IV: Screening and Extracting Data .”
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