Skip to main content

Lorenz curve

Lorenz curve A graph which is used in the study of social stratification in order to show the extent to which the actual distribution of a particular good (usually income, earnings, or wealth) deviates from a condition of perfect equality.

In the hypothetical example shown in Figure 5, the cumulated percentage of income recipients is plotted against the cumulated percentage of total income, for two separate time periods. In each case, the researcher is posing the question ‘What proportion of total income is received by 5 per cent, 10 per cent, 15 per cent (and so on) of all income recipients?’ (In this case families are the unit of analysis.) If every family had the same income, the first 5 per cent of families would have 5 per cent of all income, the first 10 per cent would have 10 per cent of all income, and so on. These points, plotted on the graph, would form a straight line (a gradient of one for one) on the diagonal at 45 degrees, This is the line of complete equality. If, on the other hand, all income went to one recipient, the points plotted would lie along the horizontal axis (5 per cent of recipients receive zero per cent of total income, as do 10 per cent, 20 per cent, and on), until—at almost 100 per cent of the recipients–the line would extend straight up the vertical axis.

Real distributions will tend to form curves lying somewhere between these two extremes. The nearer the curve is towards the line of complete equality, the more equal the distribution; the nearer it is towards the rectangular boundary, the more unequal the distribution. In the figure shown, for example, the curves suggest that the degree of income inequality was greater at time i that an time ii. See also GINI COEFFICIENT; INCOME DISTRIBUTION

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Lorenz curve." A Dictionary of Sociology. . 26 Mar. 2019 <>.

"Lorenz curve." A Dictionary of Sociology. . (March 26, 2019).

"Lorenz curve." A Dictionary of Sociology. . Retrieved March 26, 2019 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.