CINAHL Simple Searching: Dana Medical Library

CINAHL Simple Searching

Finding search terms

The first step to performing a successful literature search is formulating a good search question, then identifying the searchable concepts. For example, suppose you want to search the literature for information about the prevention and control of accidental falls among hospitalized patients. The searchable concepts here are "accidental falls" and "inpatients". When searching CINAHL using the Ovid system, you will search for each of these terms separately to bring up all articles in the database on that topic. Then, in a separate step you will combine the sets to bring up articles that contain both concepts.

About CINAHL subject headings

When the first edition of the Cumulative Index to Nursing & Allied Health literature was published in 1956, the desktop computer was still decades away from development and Internet search engines were just a glimmer in some computer scientist's eye. Articles were manually indexed using 3 x 5 index cards, from which yearly compilations were created. Not only did the finished indexes have sections for authors and titles of articles published in the past year, they also collated articles according to their subjects. To create the subject index, an official vocabulary list of descriptive terms called "CINAHL Subject Headings" was created, and each article was assigned as many terms as necessary to describe its content. For example, suppose there was a study of the causes of falls among elderly patients in a nursing home in Nebraska. The subject headings assigned to that article would include "Accidental Falls", "Aged", "Inpatients", "Nursing Homes", and "Nebraska". These terms were added to the database record for that article, along with the information about the author, title, date, and journal. Later, when the CINAHL database is searched using those subject headings, that article would be found.

Now, of course, powerful computers, sophisticated software, and reliable Internet connections have made it possible to conduct rapid keyword searches in a fraction of a second. Nevertheless, because of its superior ability to deliver highly focused, relevant results, the original database architecture based on subject headings has been retained by many indexes of professional literature, including CINAHL. Although keyword searches can be done in CINAHL, searching by subject headings is the method of choice. For any search term entered, the Ovid software will automatically display a list of appropriate CINAHL subject headings from which to make selections.

When no available subject heading adequately describes a particular concept, a keyword search is appropriate. Examples include searching for proper names, trade names, specialized jargon, and newly coined terms. A keyword search also may be used to force the system to return results, which can then be used to determine the appropriate subject headings.

Try a sample search

Using the above example, begin by connecting to CINAHL. Then,

For the first concept, enter "accidental falls" in the search box. Click Search, or simply press the Enter key.
In the Mapping Display, check the box next to the CINAHL subject heading "accidental falls". Click Continue.
Browse the list of available subheadings. You can select one or more subheadings, or chose to Include All Subheadings. In this case, check the box next to the subheading "Prevention and Control". Click Continue. You will now be back at the Main Search Page, having generated the first set of your literature search.
Now enter the second term, "inpatients", in the search box, and click Continue.
From the Mapping Display, check the box next to the CINAHL subject heading "inpatients", and click Continue.
In the Subheading Display, check the box to Include All Subheadings, and click Continue.
You will again be back at the Main Search Page. You have now created two separate sets of results, one for "accidental falls" and another for "inpatients".

Combining sets

Now that you've created a separate set for each concept, you'll need to combine them. This is where you'll need to understand the use of the Boolean operators AND and OR, which you may remember from your days of studying of algebra. The Boolean operator AND will generate a set of articles each of which contains all the selected terms. Conversely, the Boolean operator OR will generate a set of articles each of which contains at least one of the selected terms, but not necessarily all of them.

A simple analogy would be to think in terms of making a purchase. Suppose you need to buy a car. You need to make decisions regarding type of car, color, and transmission. Let's say you decide you want a compact car, in silver, with a standard transmission. Expressed in Boolean terms, your search statement would be "compact AND silver AND standard transmission". This will bring up the rather small set of cars that satisfy all three of your criteria.

Conversely, suppose you would be perfectly happy with any car that is EITHER a compact, OR silver, OR has a standard transmission. In this case, your search statement would be "compact OR silver OR standard transmission". This will bring up a fairly large set of cars, each of which will satisfy at least one of these criteria. Thus, you will have many compact cars in a variety of colors and transmissions, many silver cars of all types and transmissions, and many cars with standard transmissions of all colors and types.

Many techniques used in database searching are based on the principles of Boolean logic. For the curious among you, the term "Boolean" comes from George Boole, the 19th century English mathematician who developed this system of logic. If you'd like to learn more, check out this web page http://newadonis.creighton.edu/HSL/searching/Boolean.html from Creighton University.

So, back to our sample search, since you want articles about accidental falls in inpatients, which Boolean operator would you use?

Limiting a search

You have now generated separate sets for each of your search terms, and combined them using the Boolean operator AND. But the resulting set of results is still very large. Since the results are displayed in reverse chronological order rather than being ranked according to relevancy, you need a mechanism to reduce the total number of hits to make the set more manageable and eliminate those results that are not directly on your topic. One very simple tool to do this is through use of limits.

The most commonly used limits are provided below the search box on the Main Search Page. The Additional Limits button contains more options, including age groups, journal subsets, and publication types such as clinical trials, practice guidelines, randomized controlled trials, meta-analysis, and review articles. Pull the scroll bar down to view the entire screen.

Limit in stepwise fashion rather than all at once so that you have the option of going back to a previous, less restricted, set if necessary.

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