Sentence definitions can sometimes be usefully enhanced with lifelike examples that serve as clarifying experiences shared by author and reader.
The purpose of an aptitude test is to estimate the capacity of people to succeed at some endeavor, such as to predict their ability to succeed in college. On the other hand, the purpose of an achievement test is to judge how well people have mastered knowledge or skills they have already studied or practiced. Sometimes the same test can serve both purposes. To illustrate, assume that two high school students take an algebra test. Their scores will reflect their achievement up to that time–what they have already learned about algebra. But their scores can also be used to estimate how well they will succeed with future studies in mathematics. A student scoring at the 95th percentile will, in the future, probably do better in math than a student at the 27th percentile.
The expression family functions refers to what family life contributes to the individuals who comprise the family. For instance, children–because they are members of a family–receive food, shelter, clothing, medical care, affection, and instruction in cultural traditions (language, customs, values). Parents–because they head a family–gain satisfaction for having produced offspring, receive affection and gratitude from their children, and enjoy the approval of outsiders for performing their childrearing duties in a responsible manner.
Defining a key term operationally consists of specifying the techniques used for measuring or assessing the characteristic that the term signifies.
In this study, academic aptitude is defined by the scores students earn on the Educational Testing Service’s computerized version of the Scholastic Aptitude Test, edition 2000.
Degree of success in elections is defined as “the percentage of votes a candidate receives out of the total number of votes cast.
The term high school grades refers to a student’s grade point average as computed by the following formula where SLGE = student’s letter grade equivalent (A = 4, B= 3, C= 2, D = 1, F = O) and CPPW = number of class periods per week for a course.
It is not necessary to limit yourself to only one of the above ways of defining terms. You may often find it best to cast one definition as a sentence, another as several sentences elaborated with lifelike examples, and a third as the procedures used for measuring the variable that is being defined. Which methods you choose can depend on (a) which type you believe will be most precisely understood by readers and (b) which type guides you most accurately in selecting datagathering techniques and interpreting the data.