Likert Scale

Categories of Response

Generally, a Likert scale presents the respondent with a statement and asks the respondent to rate the extent to which he or she agrees with it. Variations include presenting the subject with a question rather than a statement. The categories of response should be mutually exclusive and should cover the full range of opinion. Some researchers include a “don't know” option, to distinguish between respondents who do not feel sufficiently informed to give an opinion and those who are “neutral” on the topic.

Size of Likert Scales

The size of Likert scales may vary. Traditionally, researchers have employed a 5-point scale (e.g., strongly agree, agree, neutral, disagree, strongly disagree). A larger scale (e.g., seven categories) could offer more choice to respondents, but it has been suggested that people tend not to select the extreme categories in large rating scales, perhaps not wanting to appear extreme in their view. Moreover, it may not be easy for subjects to discriminate between categories that are only subtly different. On the other hand, rating scales with just three categories (e.g., poor, satisfactory, good) may not afford sufficient discrimination. A current trend is to use an even number of categories, to force respondents to come down broadly “for” or “against” a statement. Thus, 4-point or 6-point Likert scales are increasingly common.

Directionality of Likert Scales

A feature of Likert scales is their directionality: The categories of response may be increasingly positive or increasingly negative. While interpretation of a category may vary among respondents (e.g., one person's “agree” is another's “strongly agree”), all respondents should nevertheless understand that “strongly agree” is a more positive opinion than “agree.” One important consideration in the design of questionnaires is the use of reverse scoring on some items. Imagine a questionnaire with positive statements about the benefits of public health education programs (e.g., “TV campaigns are a good way to persuade people to stop smoking in the presence of children”). A subject who strongly agreed with all such statements would be presumed to have a very positive view about the benefits of this method of health education. However, perhaps the subject was not participating wholeheartedly and simply checked the same response category for each item. To ensure that respondents are reading and evaluating statements carefully, it is good practice to include a few negative statements (e.g., “Money spent on public health education programs would be better spent on research into new therapies”). If a respondent answers positively to positive statements and negatively to negative statements, the researcher may have increased confidence in the data. Thus, it is good practice to employ reverse scoring of some items.

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