page_title: Likert scale
section_title: Composition
hierarchical_section_title: Likert scale / Composition
context_page_description: A Likert scale is a psychometric scale commonly involved in research that employs questionnaires. It is the most widely used approach to scaling responses in survey research, such that the term is often used interchangeably with rating scale, although there are other types of rating scales.
  The scale is named after its inventor, psychologist Rensis Likert. Likert distinguished between a scale proper, which emerges from collective responses to a set of items, and the format in which responses are scored along a range. Technically speaking, a Likert scale refers only to the former. The difference between these two concepts has to do with the distinction Likert made between the underlying phenomenon being investigated and the means of capturing variation that points to the underlying phenomenon.
  When responding to a Likert item, respondents specify their level of agreement or disagreement on a symmetric agree-disagree scale for a series of statements. Thus, the range captures the intensity of their feelings for a given item. As such, Likert scales have found application in psychology and social sciences, statistics, business and marketing.
context_section_description: A Likert scale is the sum of responses on several Likert items.  Because many Likert scales pair each constituent Likert item with its own instance of a visual analogue scale (e.g., a horizontal line, on which the subject indicates a response by circling or checking tick-marks), an individual item is itself sometimes erroneously referred to as being or having a scale, with this error creating pervasive confusion in the literature and parlance of the field.
  A Likert item is simply a statement that the respondent is asked to evaluate by giving it a quantitative value on any kind of subjective or objective dimension, with level of agreement/disagreement being the dimension most commonly used.  Well-designed Likert items exhibit both "symmetry" and "balance". Symmetry means that they contain equal numbers of positive and negative positions whose respective distances apart are bilaterally symmetric about the "neutral"/zero value (whether or not that value is presented as a candidate). Balance means that the distance between each candidate value is the same, allowing for quantitative comparisons such as averaging to be valid across items containing more than two candidate values.
  The format of a typical five-level Likert item, for example, could be:
  Strongly disagree
  Disagree
  Neither agree nor disagree
  Agree
  Strongly agree
  Likert scaling is a bipolar scaling method, measuring either positive or negative response to a statement. Sometimes an even-point scale is used, where the middle option of "neither agree nor disagree" is not available. This is sometimes called a "forced choice" method, since the neutral option is removed. The neutral option can be seen as an easy option to take when a respondent is unsure, and so whether it is a true neutral option is questionable. A 1987 study found negligible differences between the use of "undecided" and "neutral" as the middle option in a five-point Likert scale.
   Likert scales may be subject to distortion from several causes. Respondents may:
  Avoid using extreme response categories (central tendency bias), especially out of a desire to avoid being perceived as having extremist views (an instance of social desirability bias). This effect may appear early in a test due to an expectation that questions which the subject has stronger views on may follow, such that on earlier questions one "leaves room" for stronger responses later in the test. This expectation creates bias that is especially pernicious in that its effects are not uniform throughout the test and cannot be corrected for through simple across-the-board normalization;
  Agree with statements as presented (acquiescence bias), with this effect especially strong among persons, such as children, developmentally disabled persons, and the elderly or infirm, who are subjected to a culture of institutionalization that encourages and incentivizes eagerness to please;
  Disagree with sentences as presented out of a defensive desire to avoid making erroneous statements and/or avoid negative consequences that respondents may fear will result from their answers being used against them, especially if misinterpreted and/or taken out of context;
  Provide answers that they believe will be evaluated as indicating strength or lack of weakness/dysfunction ("faking good"),
  Provide answers that they believe will be evaluated as indicating weakness or presence of impairment/pathology ("faking bad"),
  Try to portray themselves or their organization in a light that they believe the examiner or society to consider more favorable than their true beliefs (social desirability bias, the intersubjective version of objective "faking good" discussed above);
  Try to portray themselves or their organization in a light that they believe the examiner or society to consider less favorable/more unfavorable than their true beliefs (norm defiance, the intersubjective version of objective "faking bad" discussed above).
  Designing a scale with balanced keying (an equal number of positive and negative statements and, especially, an equal number of positive and negative statemen
caption: An example questionnaire about a website design, with answers as a Likert scale