Dirty Dozen Scale

Abstract

The Dirty Dozen scale (DD), developed by Peter K. Jonason and Gregory D. Webster in 2010, is a concise, 12-item self-report inventory. Its primary function is the rapid measurement of the three highly correlated, socially aversive traits that comprise the Dark Triad personality cluster: Narcissism, Machiavellianism, and Psychopathy. The scale was specifically designed to provide researchers with a time-efficient, yet psychometrically sound, alternative to much longer assessment tools, making it exceptionally useful for large-scale studies, longitudinal designs, or settings where administrative time is severely constrained. Each of the three core subscales is measured by four distinct items, allowing for both a composite Dark Triad score and individual trait scores.

Keywords

Dark Triad, Narcissism, Machiavellianism, Psychopathy, Personality Assessment, Short Form, Self-Report, Psychological Measurement, Subclinical Traits.

Authors

Peter K. Jonason, Gregory D. Webster.

[quads id=5]

Purpose

The central purpose of the Dirty Dozen scale is to offer an economical and highly efficient instrument for simultaneously assessing the key constructs of the Dark Triad. By condensing the measurement of narcissism, Machiavellianism, and psychopathy into a mere 12 items, the DD significantly reduces participant burden and research resource intensity compared to traditional, lengthy inventories.

This efficiency is paramount in modern psychological research, facilitating rapid screening in high-volume studies and minimizing participant fatigue in designs that involve multiple measures. The scale is frequently utilized to examine real-world behavioral outcomes associated with these dark traits, including unethical decision-making, aggression, interpersonal manipulation, and various relationship dynamics.

Construct

The DD is a dimensional measure of the Dark Triad, a conceptual clustering of three distinct, albeit statistically correlated, socially undesirable personality constructs. The scale captures the core variance of each component trait:

• Narcissism: Characterized by feelings of grandiosity, entitlement, superiority, and a strong drive for dominance and admiration.
• Machiavellianism: Defined by cynicism, a calculated disregard for morality, and a strategic, manipulative approach to exploiting others for personal gain.
• Subclinical Psychopathy: Marked by high impulsivity, emotional poverty, callousness, an absence of guilt or remorse, and antisocial tendencies.

Each of the 12 items was rigorously developed to ensure conceptual fidelity, capturing the unique features of its respective trait while contributing to a robust overall measure of the general Dark Triad factor. The scale permits researchers to analyze both the shared variance (the composite score) and the unique predictive power of the individual component traits.

Validity

The Dirty Dozen scale has consistently demonstrated robust construct validity across a wide range of academic investigations. Strong evidence of convergent validity has been established through significant correlations between the DD subscales and established, comprehensive measures of the Dark Triad, such as the Narcissistic Personality Inventory (NPI) and the Mach-IV scale. This confirms that the concise 12-item format accurately captures the intended psychological constructs.

Furthermore, the DD subscales exhibit expected patterns of divergent validity when correlated with established personality models, most notably the Big Five model. The traits measured by the DD consistently show significant negative relationships with high levels of Agreeableness and Conscientiousness. The scale’s validity has also been successfully tested and confirmed in diverse cultural and linguistic contexts, including studies focusing on the Persian population (Hajlo, 2014).

Reliability

Given its abbreviated nature, the Dirty Dozen scale generally exhibits strong internal consistency, making it a reliable instrument for research applications in psychological assessment. The use of four items per subscale helps maintain acceptable to good reliability coefficients, typically measured using Cronbach’s alpha (α).

Jonason et al. (2013) reported the following internal consistency estimates based on their research, demonstrating the reliable coherence of items within each subscale:

• Narcissism: α = .83
• Machiavellianism: α = .78
• Psychopathy: α = .80

Factor Analysis

The foundational validation studies, including the seminal work published by Jonason and Webster (2010), consistently supported a distinct three-factor structure. This structure directly corresponds to the three theoretical components of the Dark Triad: Narcissism, Machiavellianism, and Psychopathy. Each factor is robustly defined by four specific items that exhibit high loadings onto their respective construct.

Although the three factors are statistically correlated, reflecting their shared core of antagonism and callousness, the scale is typically scored using the three distinct subscales to allow for fine-grained differentiation of the unique psychological mechanisms associated with each trait. The standard item groupings used for calculating subscale scores are:

• Machiavellianism: Items 3, 8, 9, and 10.
• Psychopathy: Items 1, 2, 11, and 12.
• Narcissism: Items 4, 5, 6, and 7.

Instrument

Test Type: Self-report personality inventory

Format: 12 items rated on a 7-point Likert scale (1 = Strongly Disagree; 7 = Strongly Agree)

Language Available: English (Original), Persian, and numerous other translations used globally in personality research.

Population Group: General population, primarily non-clinical samples.

Age Group: Adolescents and Adults (typically 18 years and older)

Population Details: The scale is widely adopted in academic research settings, particularly within social and organizational psychology, to measure subclinical manifestations of dark personality traits in non-forensic populations.

Test Methodology: Respondents indicate their level of agreement with each statement on the 7-point scale. Subscale scores are calculated by summing the responses for the four items assigned to each component (Narcissism, Machiavellianism, Psychopathy). A total score, representing the general Dark Triad factor, is derived by summing all 12 item responses.

Keywords

Personality traits, Psychological Measurement, Subclinical traits, Callousness, Manipulation, Exploitation, Psychological Assessment, Jonason & Webster, Short Form Inventory.

[quads id=5]

Authors

Author ORCID Identifier: Not provided in source.

Affiliation Email addresses: Not provided in source.

Correspondence Address: Not provided in source.

Permissions & Fee and Test Year

The Dirty Dozen scale is a popular instrument in academic research and is generally considered to be freely available for non-commercial research and educational purposes, provided that the original authors (Jonason & Webster) are appropriately cited in any subsequent work. The scale was formally introduced and validated in 2010.

The original PDF detailing the scale and its validation can be downloaded here: http://scottbarrykaufman.com/wp-content/uploads/2013/08/jonason-et-al-2013.pdf

Reference’s

• Jonason, P. K., & Tost, J. (2010). I just cannot control myself: The Dark Triad and self-control. Personality and Individual Differences, 49, 611-615.
• Jonason, P. K., & Webster, G. D. (2010). The Dirty Dozen: A concise measure of the Dark Triad. Psychological Assessment, 22, 420-432.
• Jonason, P. K., & Webster, G. D., Geher, G. (2013). What Lies Beneath the Dark Triad Dirty Dozen: Varied Relations with the Big Five. Individual Differences Research, 11(2), 81-90.
• Hajlo N. [Construct Validity of Dark Triad Questionnaire (Persian)]. Research Plan. Ardabil: Psychology Faculty, Mohaghegh Ardabili University. 2014;70-3.

[quads id=5]

Items of the Dirty Dozen Scale

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

1. I tend to lack remorse.
2. I tend to be callous or insensitive.
3. I tend to manipulate others to get my way.
4. I tend to want others to admire me.
5. I tend to want others to pay attention to me.
6. I tend to seek prestige or status.
7. I tend to expect special favors from others.
8. I tend to exploit others towards my own end.
9. I have used deceit or lied to get my way.
10. I have used flattery to get my way.
11. I tend to be unconcerned with the morality of my actions.
12. I tend to be cynical.