Targeted Searching using Term Variants (Wildcards) – All Databases

Background

The Ovid platform provides a comprehensive selection of features and functions to help build robust search strategies that are able to cope with the complexities of both language and document composition. For instance, spelling variations are a challenge when formulating search expressions. Not only are there regional spelling differences, e.g. British versus American spelling, but also very commonly, singular and plural forms of words.

Ovid provides a comprehensive selection of so-called ‘wildcards’ to accommodate these differences. Generally speaking, wildcards are symbols that can be used as character replacement holders. Some wildcard characters can be entered with numbers to indicate the number of characters for which a place or places should be held. An overview is given in the graphic below.

Fuller details are provided in the Ovid Online Help as well as the Database Field Guide for the individual database you are searching in.

A note on searching for text strings “n” (See line #12):
Although Ovid performs phrase searching by default, quotation marks “ ” , can be used to require Ovid to search for the expression as a literal string. This is particularly helpful when the string includes special characters, such as a forward slash (/) or reserved words, such as the word ‘use’. On the Ovid platform the word ‘use’ is a reserved word in that it is interpreted as a command. In combination with a database’s abbreviation, e.g. medall for Ovid MEDLINE ALL, Ovid understands this expression as a command, i.e. use medall to change from the resource you are in, to the database, Ovid MEDLINE ALL. This being the case, the search substance use.ti,ab. would need to be entered as ”substance use”.ti,ab.

Practice Suggestions

1. Drug trade names, like ‘Ritalin’ are usually clear cut terms and do not warrant truncation with wildcard characters. That said, would there be any benefit in truncating ritalin in line #3 even in a limited way, e.g. using the search expression  ritalin*1.ti,ab. for example. How would you establish the usefulness or even a possible need for this.
2. Drawing upon the example in line #6, run the searches child$.ti,ab. and child$3.ti,ab., the latter in a separate line. Use the NOT operator to establish the difference in the numbers of results between them. What terms have you obtained with child$.ti,ab. that were excluded by child$3.ti,ab.?
3. Previous test searches using the ADJ operator for line #10 established that it could be rendered efficiently as ((randomized or randomised) adj (controlled trial or controlled trials)).ti,ab,kf.  With specific wildcards we can now further reduce this to (randomi#ed controlled trial$).ti,ab,kf.. On the face of it, these two expressions should return the same number of results. Do they? Were there to be a difference, how could you explain it?

 

Search Stategy

Copy Strategy Launch Search

Reviewers

Primary: Michael Fanning

Secondary: Charlotte Viken

Review Date: 2024-10-30

Expiry Date: 2025-10-30

Original search produced by:

Ovid Training Team

References:

Ovid / Database Field Guides
Ovid MEDLINE / Advanced Searching
Embase on Ovid / Advanced Searching

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OvidGO! / Skills Videos
What are Boolean Operators?
What is an adjacency operator?
What are wildcards?
Truncation of keywords
Phrase searching on Ovid
Subject heading searching

 

Citation:

OvidGO! Portal. Focused Searches: Targeted Searching using Term Variants (Wildcards) – All Databases [Internet]. London (UK): Ovid Training Team (Editors); 2024 [updated 25 October 2024; cited 30 October 2024]. Available from: https://tools.ovid.com/ovidgo/searches/view.php?id=54