Library Guides: Literature searching and finding evidence: Structure your search

Searching databases

Key to searching databases structuring your search effectively. You can't just type in your question or topic directly into a database and expect to find relevant results.

You need to search using terms from each concept of your topic and then combine these concepts together to retrieve your final result.

Let's use the following PICO as an example:

PICO Element	Keywords
Patient / Population / Problem	children, infants, minors, paediatric
Intervention	exercise, physical activity, exertion, sport, walking, swimming, aerobics, fitness, cycling
Comparison	diet, nutrition, eating habits, food, feeding
Outcomes	obesity, overweight, weight gain, body mass index, BMI

Your search will need to contain the search terms from each of these concepts e.g.:

children or infants or minors or paediatric
exercise or physical activity or exertion or sport or walking or swimming or aerobics or fitness or cycling
diet or nutrition or eating habits or food or feeding
obesity or overweight or weight gain or body mass index or BMI

OR is a Boolean Operator. It tells the database to search for word A or B or C etc.: it must find at least one of these words to appear in the search results, but it can be any word. OR widens your search.

Platforms like EBSCOhost and Ovid let you search for different keywords using multiple lines of search boxes and to save these searches as you go along.

Perform a separate search for each concept of your topic:

Each search you make will be added to your Search History. Combine all of these searches together using the AND operator:

to get your final result:

AND is another Boolean operator. It tells the database to search for A and B and C: it must find all of these words together in the same article in order for it to appear in the search results. AND narrows your search.

You can also search for your terms all at the same time using AND and OR simultaneously:

Other databases

Other databases may only give you one line to perform your search. If this is the case surround the different concepts of your search in brackets and combine each concept with the AND operator e.g.:

(children or infants or minors or paediatric) and (exercise or physical activity or exertion or sport or walking or swimming or aerobics or fitness or cycling) and (diet or nutrition or eating habits or food or feeding) and (obesity or overweight or weight gain or body mass index or BMI)

There are a number of other tools and techniques available to enhance your searching - see the Search Techniques.