MMPI Lie (L) Scale

Abstract

The MMPI Lie (L) Scale is a 15-item validity index designed to identify respondents who are deliberately attempting to present themselves in an unrealistically favorable or socially desirable manner during test completion. The items address attitudes and common practices that are minorly socially undesirable, such as small dishonesties, occasional aggressive feelings, or weaknesses of character. The response format is True-False, and a “False” response is scored as a lie for all items. In contemporary psychological assessment, scores of eight or higher are considered highly suggestive of purposeful self-presentation or impression management, indicating potential invalidity of the overall test profile.

Keywords

MMPI, Lie Scale, L Scale, Validity Scale, Social Desirability Responding, Impression Management, Response Bias, Psychological Assessment, Personality Inventory.

Authors

Starke R. Hathaway, J. C. McKinley

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Purpose

The primary purpose of the L scale is to serve as a straightforward validity indicator within the Minnesota Multiphasic Personality Inventory (MMPI). It specifically targets a conscious and unsophisticated attempt by the respondent to portray themselves as morally superior or flawless, a behavior often termed “faking good.”

The scale measures the degree to which an individual denies minor, ubiquitous character flaws or common, slightly undesirable actions. Because the items are transparent regarding their desirable response, high scores suggest that the test protocol may be compromised due to the respondent’s effort to exhibit extreme social desirability, particularly among naive or less sophisticated test-takers.

Construct

The L scale is fundamentally a measure of Social Desirability Responding (SDR), focusing specifically on the component known as impression management. Impression management refers to the deliberate effort to control self-presentation to influence the perceptions of others, a strategy distinct from self-deception (the honest, though biased, belief in one’s own perfection).

The transparency of the items led the constructors to observe that the scale functions as a “trap for the naive subject” (Meehl & Hathaway, 1946). Consequently, the L scale is often construed as an inverse measure of psychological sophistication, as college-educated persons or those of higher socioeconomic status rarely score highly. A high score in these populations may indicate a gross lack of insight into their own behavior (Greene, 1980).

Validity

Convergent Validity

The L scale demonstrates strong evidence for concurrent validity, showing high correlations with other established measures of socially desirable responding. Examples include Eysenck’s Lie scale (Paulhus, 1986) and the Marlowe-Crowne Social Desirability Scale (Edwards & Walsh, 1964). The scale reliably loads on the second factor of SDR, confirming its role as a measure of conscious impression management.

It is important to emphasize that high scores on the L scale are not claimed to predict lying behavior outside of self-report contexts. In one known laboratory study, however, high scorers demonstrated superior performance compared to low scorers when facing a stressful situation (Burish & Houston, 1976), possibly reflecting a generalized ability to maintain a positive facade under pressure.

Discriminant Validity

The L measure shows comparatively low correlations with measures that load on the first factor of SDR (self-deception). For instance, correlations between the L scale and the MMPI K scale—an alternative and more subtle SDR measure—typically range from low to moderate (Dahlstrom, Welsh, & Dahlstrom, 1972), supporting the distinction between conscious faking and unconscious defensiveness.

Reliability

Internal Consistency

Internal consistency studies have yielded moderate results. Gocka (1965) reported an alpha coefficient of .72 on a patient sample. A separate study utilizing a student sample reported a slightly lower alpha value of .60 (Paulhus, 1984). These values suggest acceptable internal reliability, consistent with the nature of a short validity scale.

Test-Retest Reliability

Test-retest correlations show strong stability over short intervals, with correlations for periods up to one week ranging from .70 to .85. However, stability decreases significantly over longer periods. For intervals of one year or more, correlations drop, ranging from .35 to .60 (Greene, 1980; Rorer & Goldberg, 1965). This variability suggests that the measured tendency toward naive self-enhancement may change over time, perhaps as subjects gain test-taking sophistication.

Factor Analysis

The L scale consistently loads primarily on the second major factor of Social Desirability Responding (SDR), which represents the dimension of impression management. This factor is associated with the conscious, deliberate attempt to provide an overly positive self-report. Its low correlation with the first factor of SDR (self-deception enhancement, typically measured by the K scale) confirms its specific focus on overt attempts to “fake good.”

Instrument

Test Type: Objective Personality Inventory Validity Scale

Format: 15 True/False items

Language Available: English (Original), widely available in numerous translations as part of the full MMPI battery.

Population Group: Adolescents and Adults

Age Group: Typically 16 years and older, corresponding to the standardized population for the MMPI.

Population Details: Normative data includes general populations, college students (e.g., means of 2.5 for males and 2.7 for females reported by Goldberg, 1972), and large samples of medical outpatients (e.g., means of 4.2 for males and 4.8 for females reported by Swenson et al., 1973).

Test Methodology: Self-report questionnaire, scored by assigning one point for each “False” response to the 15 keyed items.

Keywords

Validity Indicator, Psychological Assessment, Faking Good, Response Style, Hathaway, McKinley, Alpha Coefficient, Test Bias, Test-Retest Reliability.

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Authors

Author ORCID Identifier: Not specified in source content.

Affiliation Email addresses: Not specified in source content.

Correspondence Address: Psychological Corporation (Original Publisher).

Permissions & Fee and Test Year

The L scale was developed as part of the original MMPI, with the manual published in 1951 by Hathaway and McKinley. Permissions and usage fees are governed by the current publisher of the MMPI/MMPI-2/MMPI-3, requiring appropriate professional licensing for administration and scoring.

Reference’s

• Dahlstrom, W. G., Welsh, G. S., & Dahlstrom, L. E. (1972). An MMPI handbook (Vol. 1). Minneapolis: University of Minnesota Press.
• Hathaway, S. R., & McKinley, J. C. (1951). MMPI manual. New York: Psychological Corporation.
• Greene, R. L. (1980). The MMPI: An interpretive manual. New York: Grune & Stratton.

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Items of the MMPI Lie (L) Scale

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

Sample Items

1. At times I feel like swearing. (F)

   TRUE FALSE

2. I get angry sometimes. (F)

3. Sometimes when I am not feeling well I am cross. (F)

Complete Scale

The MMPI booklet numbers for the 15-item Lie scale are 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 195, 225, 255, 285. All items are keyed negatively, that is, one point is assigned for each “False.”