© Copyright 2000 State University of New York & Ulster County Community CollegeUsing a Little Logic
Remember when you took algebra and combined expressions such as (a+b) + (2a - 4b), or in logic where you looked at the Boolean operators AND, OR, NOT and circle drawings called Venn Diagrams? You do? Great! Searching online will be no problem. But just in case you need a refresher on these concepts, let's look again at the research project on the aged for that sociology class assignment.
After you key in the correct term (aged) for the subject or descriptor, the computer scans all the records in a medical database and comes up with thousands of records. The computer does not evaluate these records; it just matches whatever terms you keyed in. Unless you have no life, (and therefore, have time to look through thousands of records) you want to reduce that number. How can you do it? One way is to use a Boolean operator to narrow the search.
AND
What is it you want to know about the aged? The aged AND WHAT? Exercise? Care? Diet? Vitamins? Mobility? Let's say you decide to focus on the effects of exercise on the aged. How would you do it? Search the subject field for exercise AND aged. The computer looks at subject fields which have both terms and selects only those articles that are described as dealing with BOTH aged and exercise in the subject field. Let's look at a diagram to illustrate this point. It is called a Venn diagram.
