Responsible Literature Searching Guide

Limits/Filters

The terms "limits" and "filters" are often used interchangeably. The purpose of limits or filters is to narrow search results based on selected criteria, such as publication types, age, language, or years. Most databases have integrated tools to limit search results. It is important to review the database’s Help section as limits and their applications vary.

Limits:

• May be available in either the Basic or Advanced interface.
• May default to common limits as well as may be customizable.
• Can be applied before or after the search. However, since searching is an iterative process, it is recommended to apply limits after conducting the search.

Limits should be applied carefully.

• Applying too many limits may produce too few or even no results.
• Selecting the full-text limit may eliminate relevant records from the search. For example, if the searcher limits an Ovid search to full text, the limited results will include only those results with full text available through the UT Southwestern Library’s Ovid subscription. The searcher will miss relevant articles available in other UT Southwestern subscribed databases, such as CINAHL, Springer, ClinicalKey, etc.
• Each database interprets limit commands differently; refer to the database’s Help section for more information. For example:
  • In PubMed, limits from an existing search will carry over in a subsequent search unless manually cleared by the searcher.
  • In Ovid's "Additional Limits" feature, the order of preference is applied if the searcher applies multiple limits at one time.

Common limits include:

• Publication dates (i.e., last year, last 5 years, etc.)
• Language
• Human
• Article/Publication type
• Age

PubMed, the Ovid databases, and CINAHL offer an additional limit: Clinical Queries, which are online search filters that clinicians may use to improve the timely retrieval of scientifically strong and clinically relevant articles. The Library has added Clinical Queries to the aforementioned databases’ default limits. While there are nine Clinical Queries categories, the number available in the listed databases varies. A detailed explanation of these search filters can be found at McMaster University's Hedges Project (linked below).

For additional information on available limits/filters, refer to the database’s Help section.

(Jankowski, 2008; U.S. National Library of Medicine, 2019; Waltho, Kaur, Haynes, Farrokhyar, & Thoma, 2015; Welch Medical Library, 2019; Wessel, 2019; Wolters Kluwer, 2019)

References

Health Information Research Unit. (Last Update February 9, 2016). Hedges. Retrieved from https://hiru.mcmaster.ca/hiru/HIRU_Hedges_home.aspx

Jankowski, T. A. (2008). The Medical Library Association Essential Guide to Becoming an Expert Searcher: Proven Techniques, Strategies, and Tips for Finding Health Information. New York: Neal-Schuman Publishers.

U.S. National Library of Medicine. (2019, November 15, 2019). PubMed User Guide. Retrieved from https://pubmed.ncbi.nlm.nih.gov/help/

Waltho, D., Kaur, M. N., Haynes, R. B., Farrokhyar, F., & Thoma, A. (2015). Users' guide to the surgical literature: how to perform a high-quality literature search. Can J Surg, 58(5), 349-358. doi:10.1503/cjs.017314

Welch Medical Library, J. H. U., School of Medicine. (2019). Expert Searching. Retrieved from https://browse.welch.jhmi.edu/searching

Wessel, C. B. (2019). Responsible Literature Searching for Research: A Self-Paced Interactive Program. Retrieved from https://cme.hs.pitt.edu/ISER/app/learner/loadModule?moduleId=8381&dev=false

Wolters Kluwer. (2019). Ovid Help. Retrieved from http://site.ovid.com/site/help/documentation/osp/en/index.htm#CSHID=advanced.htm