Savvy Searcher

MeSH Terms

MeSH terms and other systems of controlled vocabulary are integral to database construction and database searching. By understanding what MeSH terms are and how they are used, you can become a better database searcher and find information more quickly and effectively.

What are MeSH terms?
MeSH stands for Medical Subject Heading. MeSH terms are used to describe individual journal articles so that each time a particular topic is discussed, the same MeSH term is used to describe it. By using MeSH terms, you can be certain that you will find every article on a particular subject, because each article will be associated with the same MeSH term. For example, if you are interested in breast cancer, you would search using the MeSH term "Breast Neoplasms" to retrieve every article on this topic no matter what terminology the author used to describe the topic (breast neoplasms, breast cancer, cancer of the breast, breast carcinoma, etc.).

MeSH is a controlled vocabulary system. This means that the terms used to describe different concepts have been determined in advance and are carefully defined. The MeSH system is used in databases such as MEDLINE and HealthSTAR. Additional databases such as CINAHL use their own controlled vocabulary systems.

MeSH terms are arranged in a 'tree' from broadest to most specific. For instance, Breast Neoplasms appears in the part of the MeSH tree where Neoplasms by Site is a broader term and Male Breast Neoplasms, Mammary Neoplasms, and Experimental Mammary Neoplasms are narrower terms.

Selecting a MeSH Term
When you're trying to decide which MeSH term to use for a particular topic, you should always try to find the most specific term available. For example, if you search for articles on "Breast Cancer" you will get articles that are on breast cancer in general but you will not retrieve articles that discuss the more specific forms of breast cancer listed in the MeSH tree above (for example, Male Breast Neoplasms). You should always try to locate the MeSH term that most specifically describes your topic.

MeSH terms are assigned to individual articles by professional indexers who work for the National Library of Medicine. These expert indexers read each article and determine which MeSH terms best describe its contents. Each article has several MeSH terms associated with it. For instance, an article on the use of tamoxifen to treat breast cancer would include the following MeSH terms:

*Breast Neoplasms
*Tamoxifen
*Hormonal Antineoplastic Agents
Human
Female
Adult

Some of these MeSH terms describe the main topics of the article (Breast Neoplasms, Tamoxifen, and Hormonal Antineoplastic Agents). These MeSH terms are denoted by an asterisk (*) next to them and are known as Major MeSH terms.

Other MeSH terms describe more peripheral aspects of the article (Human, Female, and Adult), and are known as Minor MeSH terms. While these MeSH terms don't describe the primary subjects of the article, these terms contain important information to help you find research relevant to your patients.

What is term mapping?
Term mapping is a feature offered by some databases including Himmelfarb Library's Ovid databases (MEDLINE, HealthSTAR, CINAHL, etc.). This database feature is a built-in function where you provide a topic and the system will suggest which MeSH terms or terms are available to describe that topic. The term mapping features allows you to read about each MeSH term through scope notes (definitions), and then choose the one(s) that best describe your interests.

For example, if you type the topic "health care proxy", the system would match health care proxy against its thesaurus of MeSH terms and provide you with a list of MeSH terms:

You could look through this list, clicking on the "i" icon to read the scope notes of any terms in which you're interested, to decide which term or terms best describes your interests.

How are MeSH subheadings used?
Subheadings are terms that are added to MeSH terms to further describe a topic. Subheadings describe the type of information an article contains on a particular topic. A subheading will indicate whether an article discusses diagnosing, treating, or preventing a particular condition. As an example, look at the following MeSH term with subheading: *Breast Neoplasms / Drug Therapy

In this case, the subheading "Drug Therapy" specifies the type of information on Breast Neoplasms that the article contains. Commonly used subheadings for clinical concepts include:

Diagnosis
Etiology
Drug Therapy
Nursing
Prevention and Control
Therapy
Surgery
Transmission

Subheadings can be extremely helpful in focusing a search on the type of information that you want. You can choose more than one subheading to describe the type of information that you want to find. The system will return articles that contain any of those subheadings.

For instance, if you're looking for information on treating breast cancer, you might choose the subheadings Diet Therapy, Drug Therapy, Radiotherapy, Surgery, and Therapy to retrieve articles where any of these subheadings appear with the MeSH term Breast Neoplasms.

Tips
Now that you know a bit more about MeSH terms and how they are used, here are a few tips for more effective searches.

• Select the most specific MeSH term available for your topic. Read the scope notes to determine if the MeSH term really describes your topic.
• Read the subheadings carefully, and choose the one(s) that best describe what you want to know about that topic.
• Read the subheadings carefully, and choose the one(s) that best describe what you want to know about that topic.