Topic: Systematic Searching for Evidence Synthesis

Scopus is a very large, multidisciplinary database. Most evidence synthesis projects include one major database of this kind, and Scopus is the one we recommend. Web of Science, to which we do not subscribe, is its major competitor.

In terms of journal title coverage, Scopus has an almost 99% overlap with both Embase and MEDLINE. It also includes unique content not found in those two databases.

Unlike some disciplinary databases, Scopus does not have its own controlled vocabulary, so you'll only be doing keyword searching. Scopus records may include "indexed keywords," which are subject headings from other database thesauri, such as MeSH from MEDLINE, or Emtree from Embase. They are not fully consistent with what you'd see for the same reference in one of those databases, however, and you can't search any thesauri in Scopus, so it can't serve as a substitute for searching MEDLINE, Embase, or other databases with unique controlled vocabulary.

Scopus offers two wildcards.

? (question mark): A ? represents a single character. For example, wom?n finds woman or women.

* (asterisk): A * represents zero or more characters and can be used anywhere in a string of characters, including at the beginning. That said, it's most frequently used at the end for truncation purposes. For example, wom* finds woman, women, or wombats; computer* finds computer, computers, or computerize. * can be used on any or all words in a loose phrase, such as "health* wom*" for healthy women or women's health (remember, in a loose phrase, the words must be in the same field, but not necessarily next to one another).

Phrase Searching

Scopus offers two main phrase searching options:

{exact phrase}, in which your terms are enclosed in curly brackets, requires that the words appear next to each other, in that order, with no other spaces, punctuation, or truncation. For example: TITLE-ABS-KEY({heart attack}) finds heart attack, but not heart attacks.

"loose phrase", with terms in quotation marks, requires that the words appear in the same field. In loose phrases, you can use truncation on any or all words. For example, TITLE-ABS-KEY("heart attack*") finds sources with heart attack or heart attacks as a phrase or separately in either title, abstract, or keyword fields. It won't find sources with heart palpitations in the title plus anxiety attacks in the abstract.

Proximity Searching

In proximity or adjacency searching, you can tell the database to look for words near each other in a variety of ways. Scopus offers two proximity operators: Pre/n and W/n

Preceding, which uses the format Pre/n, finds words when they precede another word by no more than n words, where n is the number of your choosing. For example, zika Pre/2 virus finds zika virus as well as zika and dengue virus.

Within, which uses the format W/n, finds words within n words of one another, in any order. For example, zika W/2 virus finds virus infection with zika, virus like zika, zika virus, and even virus, zika.

Some helpful terminology here: a database includes many records. Each record is a collection of information about a single item, such as an article. Records are made up of fields, sections of the record that provides a specific piece of information about the item described (the title, the author, the abstract, etc.). Which fields interest you, and how they're searched, differs from database to database.

Since Scopus does not have its own controlled vocabulary, you'll only be doing keyword searching. The default search fields, which work well for systematic searching, are title, abstract, author keywords, and index terms. This default set of fields is abbreviated in the search as TITLE-ABS-KEY.

In general, your best strategy is to set up each concept in your research question as a single search, then combine those searches with AND. You can do this from either the basic or advanced document search screens. Below is how the basic search looks. Leave the drop-down to the default Article title, Abstract, Keywords. Use the search box to enter a search for your first concept.

After you've completed each of your main concept searches, return to the search page and scroll down to your Search History. Select the searches you want to combine. If you've used one search per concept, as in the example below, you can select all your concepts. Tap Combine queries.

In the Combine queries box, the default is to combine with AND, which is appropriate in this example. Tap Show results. 

You can export all results from an Scopus search, up to 20,000 citations. Check the box to select All above your search results, then tap Export.

Choose RIS Format.

Choose any or all available fields to include in your export.

If there are more than 20,000 items in your results, Scopus will warn you that an RIS file can only support the first 20,000. You can work around this by using date limits in your results to create batches of 20,000 or fewer items.

An RIS file will download. You can import the RIS file into the citation management tool of your choice.