Systematic Review Meta-Analysis Course - Search Assignment

The first step in building a good search is to identify your search terms, which will be a combination of controlled vocabulary and keywords. Often people wonder where to start.

The Value of Key Papers

When conducting a systematic review, you have almost always identified a few key papers you know you want your search to retrieve. In this class, you are working from a pre-existing systematic review where the included studies represent those key papers.

Note: Included studies are only those studies that are included in the analysis of your pre-existing systematic review. Do not confuse included studies with the complete reference list. You will likely need to consult the reference list, however, to find the titles of the included papers, as a precursor to locating them in PubMed.

The value of these papers is twofold. First, these papers provide a rich source to identify search terms to represent the concepts in your research question. Second, they can also be used to evaluate your final strategies to ensure you haven’t missed any important terms.

Using PubMed to Find Search Terms

PubMed is a valuable resource for identifying search terms. Each record for a key paper includes a unique ID (PMID), citation, and often an abstract and author supplied keywords. If the article has been indexed for MEDLINE, it will also have a list of assigned MeSH terms, the controlled vocabulary used in PubMed.

It is possible to make a list of the PMIDs so you can generate a set of papers at the beginning of the search process and revisit it at the end without having to look them up again.

1. Look up the included studies in your group’s systematic review in PubMed by using the "Single Citation Matcher" or the title field in the "PubMed Advanced Search Builder."
   Note: The Yale MeSH Analyzer (see below) has a maximum input of 20 PMIDs at a time. You only need to look up 8-10 included studies for this assignment. Your pre-existing systematic review may have more or less than 10 included studies.
2. Put these papers in the PubMed Clipboard by selecting the "Send to" option at the top of the results page and choosing the destination as "Clipboard."
3. To generate a list of PMIDs from your Clipboard, select "Save," choose "Selection: All Results" , and choose "Format: PMID."
4. Save or open the file to access the list of PMIDs for the selected papers.
5. You can copy and paste this list into the Word document used to record your PubMed search. You can also copy and paste this list into the Yale MeSH Analyzer search box without any additional formatting (see below).

Use the Yale MeSH Analyzer to generate an Excel file of MeSH terms and author-supplied keywords from your PMID list of included studies.

1. Go to: http://mesh.med.yale.edu/
2. Copy your list of PMIDs into the search box (no formatting required)
3. Scroll down and select the following options
   • Subheadings: Full
   • Article Titles: Full
   • Journal Titles: Full
   • Show: check all
   • Output: Excel
4. Click the "Go!" button
5. Save the Excel file for use in class