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Types Of Scales

Types Of Scales Used In Social Science Research And How To Construct Them

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A scale is a type of composite measure that is composed of several items that have a logical or empirical structure among them. That is, scales take advantage of differences in intensity among the indicators of a variable. For example, when a question has the response choices of "always," "sometimes," "rarely," and "never," this is a scale because the answer choices are rank-ordered and have differences in intensity. Another example would be "strongly agree," "agree," "neither agree nor disagree," "disagree," "strongly disagree."

There are several different types of scales. In this article, we’ll look at four commonly used scales in social science research and how they are constructed.

Likert Scale

Likert scales are one of the most commonly used scales in social science research. It is named after its creator, psychologist Rensis Likert. On a survey or questionnaire, the Likert scale typically has the following format:

  • Strongly agree
  • Agree
  • Neither agree nor disagree
  • Disagree
  • Strongly disagree
It should be noted that the individual questions that use this format are called Likert items while the Likert scale is a sum of several Likert items. To create the scale, each answer choice is assigned a score (say 0-4) and the answers for several Likert items (that measure the same concept) can be summed together for each individual to get an overall Likert score.

For example, let’s say that we are interested in measuring prejudice against women. One way to do that would be to create a series of statements reflecting prejudice ideas, each with the Likert response categories listed above. One of the items might be "women shouldn’t be allowed to vote" while another might be "women can’t drive as well as men." We would then assign each of the response categories a score of 0 to 4 (for example, assign a score of 0 to "strongly disagree," a 1 to "disagree," a 2 to "neither agree or disagree," etc.). The scores for each of the statements would then be summed for each respondent to create an overall score of prejudice. If we had 5 statements and a respondent answered "strongly agree" to each item, his or her overall prejudice score would be 20, indicating a very high degree of prejudice against women.

Bogardus Social Distance Scale

The Bogardus social distance scale was created by Emory Bogardus as a technique for measuring the willingness of people to participate in social relations with other kinds of people.

Let’s say we are interested in the extent to which U.S. Christians are willing to associate with, say, Muslims. We might ask the following questions:

1. Are you willing to live in the same country as Muslims?
2. Are you willing to live in the same community as Muslims?
3. Are you willing to live in the same neighborhood as Muslims?
4. Are you willing to live next door to a Muslim?
5. Are you willing to let your child marry a Muslim?

The clear differences in intensity suggest a structure among the items. Presumably if a person is willing to accept a certain association, he or she is willing to accept all those that precede it on the list (those with lesser intensities).

The Bogardus scale demonstrates that scales can be important data reduction tools. By knowing how many relationships with Muslims a given respondent will accept, we know which relationships were accepted. A single number can thus accurately summarize five or six data items without a loss of information.

Thurstone Scale

The Thurstone scale, created by Louis Thurstone, is intended to develop a format for generating groups of indicators of a variable that have an empirical structure among them. For example, if you were studying discrimination, you would put together a list of items (we’ll use 10 items in this example) and then ask respondents to assign scores of 1 to 10 to each item. In essence, they are ranking the items in order of which is the weakest indicator of discrimination all the way to which is the strongest indicator.

Once the respondents have scored the items, the researcher examines the scores assigned to each item by all the respondents to determine which items the respondents agreed upon the most. If the scale items were adequately developed and scored, the economy and effectiveness of data reduction present in the Bogardus social distance scale would appear.

Semantic Differential Scale

The semantic differential scale asks respondents of a questionnaire to choose between two opposite positions using qualifiers to bridge the gap between them. Let’s look at an example. Suppose you wanted to get respondents’ opinions about a new comedy television show. You must first decide what dimensions you wish to measure and then find two opposite terms that represent those dimensions. For example, "enjoyable" and "unenjoyable," "funny" and "not funny," "relatable" and "not relatable." You would then create a rating sheet for each respondent to indicate how they feel about the television show in each dimension. Your questionnaire would look something like this:

                Very Much     Somewhat     Neither      Somewhat     Very Much
Enjoyable                             X                                                                     Unenjoyable
Funny                                                                                             X          Not Funny
Relatable                                                 X                                                  Unrelatable

References

Babbie, E. (2001). The Practice of Social Research: 9th Edition. Belmont, CA: Wadsworth Thomson.

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