Ascension - WI

Better Searching

This page focuses on different methods that are useful when searching the web and databases.

When you know your topic and want to explore what else has been written, you will search for articles, books, dissertations, and other types of publications in various databases and/or search engines. It is important and useful to know how different search terms work in databases. Here, we will cover keyword and subject searches.

A keyword search involves typing into the search box the terms that you use when you think about your topic.

A subject or descriptor search means that you have identified (usually through keyword searching and looking at your results) the specific terminology used in a database to talk about your subject.  Subject headings, such as Medical Subject Headings (MeSH) that are used in Medline/PubMed, and descriptor terms tend to be more formal and also more precise (less ambiguous)

A good example is the term teenager. We use that term in everyday speech and authors may use it in their articles, but a database is most likely to assign the subject heading of adolescents.

Boolean Logic

Boolean logic, a form of algebraic logic (named after mathematician George Boole) is a system of logic designed to yield optimal search results. The Boolean operators, AND, OR, and NOT, help you construct a logical search. Boolean operators act on sets -- groups of records containing a particular word or concept.

The circle diagrams (Venn diagrams) that help illustrate the relationships between the sets used in Boolean logic were named after another mathematician, John Venn. (The shading represents the outcome of the Boolean operation.)

The Boolean Operator "AND"

When terms/concepts are combined with the AND operator, retrieved records must contain all the terms. For example: "Does taking aspirin cause Reye's Syndrome in children?" This will retrieve citations that discuss all three concepts in each article. The more concepts you AND together, the fewer records you will retrieve.

The Boolean Operator "OR"

The Boolean operator OR allows you to broaden a concept and include synonyms. For example, kidney disease OR renal diseases will retrieve citations using either (or both) terms. This expands your search by retrieving citations in which either or both terms appear. The more concepts or keywords you OR together, the more records you will retrieve.

The Boolean Operator "NOT"

The final Boolean operator NOT allows you to exclude concepts not relevant to your search. For example, you could search multi-infarct dementia by using Dementia NOT Alzheimer's. Caveat: be careful with NOT as it can eliminate too much.  In this instance,  you would eliminate records discussing both types of dementia, as all articles discussing Alzheimer's are eliminated.

Mixing Boolean Operators ( Nesting )

Nesting, or mixing the Boolean operators, is a way to combine several search statements into one comprehensive search statement. Use parentheses ( ) to separate keywords when you are using more than one operator and three or more keywords. The order in which the operations (AND, OR , NOT) are processed can vary between systems. Searches within parentheses are performed first and operations proceed from left to right. For example, diet therapy AND (bulimia OR anorexia) will retrieve records containing the two concepts, Bulimia + Diet Therapy, or the two concepts, Anorexia + Diet Therapy, or records that contain all three concepts, Bulimia + Diet Therapy + Anorexia. 

If you don't put in the parentheses, the search statement is processed strictly from left to right, so that the AND is done first. This search strategy will retrieve records containing both of the concepts, Diet Therapy + Bulimia, or any records with the concept Anorexia.

Images from Wikimedia Commons

Relevance in an era of tailored search results

While many of us have come to expect relevant search results as part of any web or app search, evaluating the relevance of search results requires a search filter or critical evaluation skills.

Popular Searches

While a restaurant app like Yelp can give you a list of local places to eat, keep in mind that your zip code is a mediating factor in this search. Your zip code limits the results thus building relevance into the search results.

Likewise, you may see ads in Facebook or Amazon.com that seem related to your latest status update or product search. In this case the mediating factor is your FB status or a DVD you recently browsed. But, imagine if you changed one of those mediating factors. If you searched for “Sandburg” using Google in a Milwaukee zip code, the first hit will be “Carl Sandburg Hall”. If you were to do this search in Chicago, the first several results will be about Carl Sandburg’s poetry.  These filter bubbles tend to be different among individuals and can reinforce bias.

Scholarly Searches

In academic research, popularity and location are not necessarily effective or useful ways to mediate a search. This is why we focus on selecting a set of search terms that will lead to the best results. In academic research, you will choose your vocabulary carefully to build mediating factors into your search, evaluate the results for relevance to your topic and then edit your search with new or different vocabularies as you continue searching.

Learning Objectives

• Recognizes various library search methods
• Identifies the differences between a popular vs scholarly search
• Based on the research topic or question, utilizes appropriate library search method
• Evaluates relevance of search results in relation to the research topic or question