Ovid Hints:
Limiting

Through its Limit functions, the Ovid system offers many opportunities to fine-tune your search and save yourself the time and energy you might otherwise spend scanning numerous irrelevant citations.

The Limit icon appears at the top of the Main Search page. Some of the features available as Limits in Ovid include:
§ age groups
§ gender
§ population groups (human or animal)
§ publication types
§ journal subsets and
§ language.

Age Groups
The most popular and well-constructed databases (MEDLINE, CINAHL, PsycINFO) have rigorous rules for indexing by these limiting parameters. Age groups are well defined so that when it is appropriate, you may limit your search retrieval to only those articles that include people in the age group of interest. This is particularly helpful in pediatrics and geriatrics/gerontology. One or more age groups may be selected. MEDLINE and CINAHL use the same age groups:
§ Infant--1-23 months old
§ Preschool Child--2-5 years old
§ Child--6-12 years old
§ Adolescence--13-18 years old
§ Adult--19-44 years old
§ Middle Age--45-64 years old
§ Aged--65 years old and older
§ Aged, 80 and over
Other databases have age groups that are meaningful to the type of material that they cover.

Gender & Population
If the gender of the patient is significant to your research, it is possible to limit your retrieval to females or males from the Limit page. The same applies to the human/animal distinction. For example, when looking for information on a new drug, you can easily eliminate all of the animal studies by selecting Human on the Limit page.

Publication Type
Limits by Publication Type are available in both MEDLINE and CINAHL. They “describe the form of presentation of an article or other work.” In MEDLINE they include designations such as Review Article, Practice Guideline, Editorial, Clinical Trial, Biography and Historical Article. A complete list can be found at http://www.nlm.nih.gov/mesh/pubtypesg.html link removed. In CINAHL, a most helpful publication type is Research, which enables you to restrict your search retrieval to only articles that are reports of research studies. By making yourself aware of the publication types, you will be better able to shape a search that more closely fits your needs.

Journal Subsets
Journal Subsets allow you to restrict the articles that you retrieve to a smaller portion of the entire database. For example, MEDLINE indexes over 4,000 journals but the AIM subset includes about 125 English-language, clinically oriented journals. The Dental and Nursing subsets are useful to people in those professions who want to limit themselves to their own literature. In CINAHL there are geographical as well as topical journal subsets. CINAHL also provides a Special Interest Category that allows you to zero in on an area of practice.

Language
Although the databases we provide through the Ovid system are produced in the United States, they are international in scope and include references to articles in non-English languages. The Languages limit box allows you to select from your retrieval only articles in the language you specify. Since most of our users wish to limit to articles in the English language, this feature has been made available on the Main Search Page as well as from the Limit page. Each database puts its most frequently used limits on the Main Search Page for your convenience.

In working with patrons who come into the library as well as with those who phone us with their search problems, the Reference Librarians have observed that failure to use the Limit function in Ovid is a widespread source of ineffective searching. We hope that this brief explication will encourage you to try the Limits and that you will see how they can be of assistance to you in your searching.

-- Mary L. Marix
mmarix@lsuhsc.edu link removed