Likert

Likert refers to a psychometric scale used to measure attitudes, opinions, or beliefs. The most common form, the Likert scale, consists of a series of statements with ordered response categories such as strongly agree, agree, neutral, disagree, and strongly disagree. Respondents indicate their level of agreement, and scores are summed or averaged across items to yield a composite attitude score. The method aims to quantify subjective assessments in survey research.

The scale was developed by American social psychologist Rensis Likert in 1932, to facilitate the measurement of attitudes in large-scale studies. Classic Likert items are single statements; multiple items are combined to increase reliability. Most implementations use five or seven response points, sometimes with reverse-scored items to control for acquiescence bias.

In analysis, Likert data are often treated as interval data, allowing calculation of means and standard deviations and the use of parametric statistics, though some researchers argue the data are ordinal and nonparametric methods may be more appropriate. Reliability is commonly assessed with internal consistency measures such as Cronbach's alpha; validity is examined through factor analysis and correlation with related constructs.

Variants are called Likert-type scales, where the number of items and endpoints may vary. They are widely used in psychology, sociology, education, marketing, and organizational research to assess attitudes toward products, policies, or procedures.

Rensis Likert founded a prominent school of social research and contributed to management theory; his work helped popularize structured attitudinal measurement in the social sciences.