Social Dominance Orientation Scale (SDO7)

Abstract

The Social Dominance Orientation Scale (SDO7), developed by Ho et al. (2015), represents a major theoretical and psychometric advancement in the measurement of individual preferences for group-based hierarchy and social inequality. Rooted in Social Dominance Theory (SDT), the instrument operationalizes social dominance orientation not as a unitary, monolithic construct, but as a dual-dimensional disposition comprising two distinct, positively correlated subdimensions: SDO-Dominance (SDO-D) and SDO-Anti-egalitarianism (SDO-E). SDO-Dominance reflects support for overt, aggressive, and coercive group-based dominance—a worldview where dominant groups actively oppress and subjugate subordinate groups. Conversely, SDO-Anti-egalitarianism reflects a preference for subtle, structural, and institutional inequality, characterized by an explicit opposition to equality, inclusive social policies, and the redistribution of societal resources.

The standard full-length SDO7 scale comprises 16 items balanced equally between pro-trait and con-trait statements across both dimensions (eight items measuring SDO-D and eight items measuring SDO-E), evaluated using an authentic 7-point Likert response scale ranging from 1 (“Strongly Oppose”) to 7 (“Strongly Favor”). Extensive empirical evaluations across diverse international cohorts—including representative community, undergraduate, and cross-national samples in the United States, Israel, and the United Kingdom—confirm that SDO7 possesses robust psychometric properties. Confirmatory factor analyses consistently demonstrate that the two-factor oblique model and bifactor structures fit empirical data significantly better than traditional unidimensional specifications (such as the earlier SDO6 scale). Both subscales exhibit high internal consistency (Cronbach’s alpha typically ranging from .82 to .93), exceptional longitudinal test-retest stability, and distinct predictive validity profiles. SDO-D specifically accounts for active, hostile intergroup phenomena (e.g., support for aggressive foreign policy, police brutality, intergroup persecution), whereas SDO-E uniquely predicts opposition to affirmative action, egalitarian resource allocation, welfare policies, and inclusive marketing initiatives. As such, the SDO7 scale serves as an essential psychometric instrument across political psychology, organizational sociology, intergroup relations, consumer research, and behavioral economics.

Keywords

Social Dominance Orientation, SDO7, Social Dominance Theory, Intergroup Relations, SDO-Dominance, SDO-Anti-egalitarianism, Group-Based Hierarchy, Prejudice, System Justification, Discrimination, Psychometrics, Scale Validation

Authors

The SDO7 scale was developed, validated, and published by a collaborative team of leading researchers in social psychology and intergroup conflict:

• Arnold K. Ho, Ph.D. — Department of Psychology, University of Michigan, Ann Arbor, Michigan, USA.
• Jim Sidanius, Ph.D. (1945–2021) — Department of Psychology and Department of African and African American Studies, Harvard University, Cambridge, Massachusetts, USA; primary co-architect of Social Dominance Theory.
• Nour Kteily, Ph.D. — Kellogg School of Management, Northwestern University, Evanston, Illinois, USA.
• Jennifer Sheehy-Skeffington, Ph.D. — Department of Psychological and Behavioural Science, The London School of Economics and Political Science (LSE), London, United Kingdom.
• Felicia Pratto, Ph.D. — Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut, USA; primary co-architect of Social Dominance Theory.
• Kristin E. Henkel, Ph.D. — Independent Researcher; formerly Department of Psychology, University of Connecticut.
• Rob Foels, Ph.D. — Department of Psychology, Cleveland State University, Cleveland, Ohio, USA.
• Andrew L. Stewart, Ph.D. — Department of Psychology, Clark University, Worcester, Massachusetts, USA.

Corresponding inquiries regarding the theoretical development and psychometric modeling of the SDO7 scale are typically directed to the Department of Psychology at the University of Michigan or the Department of Psychological Sciences at the University of Connecticut.

Purpose

The principal purpose of the Social Dominance Orientation Scale (SDO7) is to provide an empirically refined, psychometrically balanced measurement of an individual’s psychological propensity toward group-based inequality and hierarchy. Within the social sciences, measuring attitudes toward social hierarchy has historically been confounded by measurement artifacts, including acquiescence response bias, unifactorial oversimplification, and collinearity between aggressive dominance and passive resistance to equality. Previous iterations of the scale, most notably the 16-item SDO6 scale (Pratto et al., 1994), treated social dominance orientation as a single global dimension, despite recurrent psychometric observations that the scale contained distinct factor clusters reflecting overt intergroup dominance versus passive resistance to equality.

The SDO7 was intentionally constructed to achieve three critical scientific and applied objectives:

1. Theoretical Bifurcation: The instrument formally operationalizes the theoretical division within Social Dominance Theory between aggressive, zero-sum, forceful intergroup subjugation (SDO-D) and structural, ideological resistance to egalitarian relations (SDO-E). This allows researchers to isolate whether prejudice toward a target group is driven by malicious hostility or by a conservative preservation of systemic privilege.
2. Elimination of Method Artifacts: Unlike earlier versions where pro-trait and con-trait items were unevenly distributed or clustered into separate methodological factors, the SDO7 incorporates a balanced subscale architecture: exactly four pro-trait items and four con-trait items per subscale. This prevents acquiescence response sets from masquerading as substantive theoretical factors.
3. Predictive Granularity Across Diverse Domains: In academic research, public policy analysis, and organizational settings, the SDO7 illuminates the psychological mechanisms underpinning resistance to social justice initiatives, institutional diversity policies, and redistributive taxation. In clinical and forensic psychology, elevated SDO scores, specifically on SDO-D, correlate with dark triad personality traits, callous-unemotional behaviors, and acceptance of coercive state practices (e.g., police brutality, military aggression, harsh criminal sentencing).

Furthermore, in consumer behavior and inclusive marketing research, the SDO7 scale has emerged as a key moderating variable. Research reveals that an individual’s level of SDO determines their affective and behavioral responses to inclusive advertising, brand positioning supporting marginalized populations (e.g., LGBTQ+ campaigns, racial diversity in leadership), and corporate social responsibility programs. Consumers high in SDO demonstrate marked backlash against brands that violate traditional social hierarchies, making the scale indispensable for understanding ideological segmentation in modern markets.

Psychological Construct

Social Dominance Orientation (SDO) represents an individual’s general attitudinal orientation toward intergroup relations, specifically reflecting whether one prefers social systems to be organized hierarchically (such that superior groups dominate inferior groups) or egalitarily (such that all social groups possess equal power, status, and material conditions). In the SDO7 operationalization, this overarching disposition is decomposed into two interrelated yet functionally divergent psychological constructs:

1. SDO-Dominance (SDO-D)

SDO-Dominance captures an active preference for overt, coercive, and hierarchical relations between social groups. It is grounded in a social-Darwinian or competitive-jungle worldview, wherein the social sphere is perceived as an inherently zero-sum battleground of survival. Individuals scoring high in SDO-D endorse the premise that dominant groups ought to proactively exercise power, enforce subjugation, and maintain lower-status groups “in their place” through force or active disenfranchisement.

Psychologically, SDO-D is characterized by:

• Overt Ingroup Dominance: Belief that certain groups are intrinsically superior and hold a natural prerogative to subjugate subordinate groups (e.g., Item 1: “Some groups of people must be kept in their place.”).
• Intergroup Aggression and Coercion: Endorsement of aggressive group actions, systemic oppression, and state-sanctioned violence against outgroups.
• Derogation of Devalued Groups: Explicit, visceral prejudice, dehumanization, and overt antagonism toward ethnic, religious, or national minorities.

2. SDO-Anti-egalitarianism (SDO-E)

SDO-Anti-egalitarianism represents a preference for unequal intergroup relations maintained through subtle, institutionalized, and non-coercive means, primarily manifested as an ideological opposition to equality. Rather than actively seeking to crush or oppress subordinate groups through direct aggression, an individual high in SDO-E objects to measures, programs, or philosophical ideals designed to equalize status, wealth, or opportunities across groups.

Psychologically, SDO-E is characterized by:

• Opposition to Structural Equality: The conviction that group equality is either fundamentally unjust, unnatural, or undesirable (e.g., Item 11: “It is unjust to try to make groups equal.”).
• Passive Maintenance of Hierarchy: Rejection of resource redistribution, welfare safety nets, affirmative action, and universal healthcare.
• Subtle and Symbolic Bias: Manifestation of modern or symbolic forms of prejudice, often cloaked in meritocratic, fair-market, or anti-interventionist rhetoric rather than overt hostility.

The Balanced Pro- and Con-Trait Architecture

A vital psychometric characteristic of both SDO-D and SDO-E within the SDO7 is the inclusion of balanced item framing. Pro-trait items measure direct agreement with dominance or anti-egalitarian principles, whereas con-trait items express pro-egalitarianism or anti-dominance principles (which are reverse-scored). This balanced structure ensures that the resultant scores reflect genuine ideological commitments rather than generalized acquiescence or cognitive processing biases.

Theoretical Framework

The theoretical bedrock of the SDO7 scale is Social Dominance Theory (SDT), first articulated by Jim Sidanius and Felicia Pratto (1999). SDT represents a comprehensive, multi-level bio-psycho-social framework that seeks to understand how group-based social hierarchies are produced, preserved, and structurally reinforced across human civilizations.

Core Assumptions of Social Dominance Theory

SDT postulates that all human societies capable of generating economic surplus inevitably organize themselves into group-based social hierarchies. These hierarchies consist of at least one hegemonic, dominant group possessing disproportionate shares of “positive social value” (e.g., wealth, political power, legal protection, healthcare, quality education) and subordinate groups bearing disproportionate burdens of “negative social value” (e.g., poverty, incarceration, disease, physical violence). Social hierarchies are typically organized around three distinct systems:

1. Age System: Where adults hold social power over children.
2. Gender/Patriarchal System: Where men disproportionately hold political and social dominance over women and non-binary individuals.
3. Arbitrary-Set System: Culturally constructed group distinctions based on ethnicity, race, nationality, religion, social caste, or social class.

Legitimizing Myths: Hierarchy-Enhancing vs. Hierarchy-Attenuating

According to SDT, societal stability in the face of massive inequality is maintained through widely shared cultural ideologies termed legitimizing myths:

• Hierarchy-Enhancing Legitimizing Myths (HEs): Ideologies, beliefs, and values that provide moral and intellectual justification for group-based inequality. Examples include racism, sexism, nationalism, internal attribution of poverty, meritocratic fundamentalism, and just-world beliefs. Individuals high in SDO are motivated to endorse HEs, utilizing them to rationalize existing disparities.
• Hierarchy-Attenuating Legitimizing Myths (HAs): Ideologies that challenge inequality and advocate for group parity. Examples include universal human rights, egalitarianism, feminism, environmental justice, and socialism. High-SDO individuals reject HAs because they threaten the existing hierarchical social order.

The Dual-Engine Model of SDO within SDT

The development of the SDO7 refined SDT by demonstrating that hierarchy maintenance operates via two distinct psychological engines. While earlier formulations viewed SDO primarily as a generalized drive for inequality, Ho et al. (2015) proved that social dominance is maintained both through aggressive conquest (SDO-D) and institutional preservation (SDO-E). This differentiation corresponds directly to classic socio-evolutionary and sociological distinctions between violent coercion (despotism) and systemic exclusion (hegemony).

Validity

The SDO7 scale has undergone rigorous empirical validation across multiple cross-sectional, longitudinal, and experimental designs involving thousands of participants across diverse cultural contexts.

Construct and Structural Validity

Structural validity was established by comparing competing factor models via confirmatory factor analysis (CFA). In the seminal validation studies by Ho et al. (2015), the hypothesized two-factor oblique model (SDO-D and SDO-E) demonstrated superior fit indices compared to a unidimensional model across independent samples of American undergraduates, U.S. national adults, British adults, and Israeli Jews. Specifically, the two-factor model yielded non-significant chi-square contributions or superior practical fit indices (CFI > .95, RMSEA < .06). Furthermore, a bifactor model—incorporating a general SDO dimension alongside specific SDO-D and SDO-E orthogonal sub-factors—also confirmed the presence of both broad shared variance and clinically meaningful sub-dimensional specificity.

Convergent and Discriminant Validity

SDO7 demonstrates robust convergent validity with theoretically aligned constructs while remaining empirically distinct from related ideological measures:

• Right-Wing Authoritarianism (RWA): In accordance with Duckitt’s Dual-Process Cognitive-Motivational Model, SDO and RWA represent two independent pathways to intergroup prejudice. CFA models confirm that SDO7 and RWA load onto separate, moderately correlated factors (typically r = .30 to .50). While RWA stems from a perception of the world as dangerous and disorderly (motivating a need for security and conformity), SDO stems from viewing the world as a competitive jungle (motivating a quest for dominance and inequality).
• Personality Correlates: SDO7 correlates negatively and robustly with the Big Five trait of Agreeableness (typically r = -.40 to -.55) and to a lesser extent with Openness to Experience (r = -.20 to -.35), confirming its conceptual alignment with tough-mindedness and self-interest.
• Dark Triad: SDO-D correlates particularly strongly with Machiavellianism, psychopathy, and everyday sadism, validating its aggressive, predatory character.

Predictive and Incremental Predictive Validity

The primary psychometric justification for the SDO7 scale lies in the distinctive predictive validity profiles of its two subdimensions. Through multivariate structural equation modeling and regression analyses, Ho et al. (2015) confirmed that SDO-D and SDO-E uniquely predict divergent social, political, and consumer outcomes:

• SDO-Dominance Uniquely Predicts: Support for aggressive militarism, foreign wars, preemptive strikes, capital punishment, enhanced interrogation techniques (torture), police use of force, and overt discrimination against low-status minority outgroups.
• SDO-Anti-egalitarianism Uniquely Predicts: Opposition to race-conscious affirmative action, redistributive tax models, minimum wage increases, environmental protection policies, government-sponsored universal health care, and corporate diversity, equity, and inclusion initiatives.

These findings demonstrate that SDO-E accounts for policy resistance even when individuals display no overt hostility, whereas SDO-D accounts for active, punitive intergroup violence.

Reliability

The SDO7 scale consistently exhibits exemplary internal consistency and temporal stability across diverse participant populations, language adaptations, and cultural settings.

Internal Consistency

Extensive psychometric evaluations by Ho et al. (2015) and subsequent independent replications across social science literature indicate that the 16-item full-scale SDO7, as well as its two 8-item subscales, possess exceptional internal reliability:

• Full Composite SDO7 (16 items): Cronbach’s alpha ($lpha$) coefficients routinely range from .90 to .95; McDonald’s omega ($\omega_t$) typically exceeds .93, reflecting exceptional total reliability.
• SDO-Dominance Subscale (8 items): Cronbach’s alpha consistently ranges between .85 and .92 across diverse U.S. and European samples.
• SDO-Anti-egalitarianism Subscale (8 items): Cronbach’s alpha consistently ranges between .84 and .93 across national community samples.

Test-Retest Stability

Longitudinal assessments confirm that Social Dominance Orientation, as measured by SDO7, behaves as a stable personality-like ideological trait. In longitudinal panel studies spanning periods ranging from several weeks to multiple months, test-retest reliability coefficients ($r_{tt}$) consistently range between .75 and .86 for both the composite score and the individual subdimensions, indicating that baseline hierarchy preferences remain highly stable over time in the absence of major macro-societal disruptions.

Factor Analysis

The internal structural validity of the SDO7 scale was established through rigorous exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) during its psychometric construction. Historical iterations of the scale, such as the SDO6, frequently produced two factors upon EFA, which were often discounted by psychometricians as methodological artifacts resulting from the unbalanced grouping of positively and negatively worded statements (the so-called “wording effects”).

Confirmatory Factor Analytic Results

To definitively untangle substantive theoretical factors from wording artifacts, Ho et al. (2015) utilized multi-group structural equation modeling incorporating both trait factors (Dominance and Anti-egalitarianism) and method factors (pro-trait and con-trait item format). The results unequivocally supported the theoretical two-dimensional model:

• Model Fit Indices: The two-factor oblique model exhibited outstanding fit across diverse adult samples: $\chi^2/df < 2.5$, CFI ranging from .96 to .98, TLI ranging from .95 to .97, and RMSEA ranging from .035 to .052 (with 90% confidence intervals well below the .08 threshold of acceptable fit).
• Standardized Factor Loadings: Standardized loadings for all 16 items onto their designated target latent factors (SDO-D or SDO-E) are uniformly high, typically ranging between .60 and .86 ($p < .001$). The reverse-scored (con-trait) items load consistently and inversely onto the theoretical factors without substantial residual cross-loadings.
• Inter-Factor Correlation: The latent correlation between the SDO-D and SDO-E dimensions typically ranges from $r = .45$ to $r = .65$. This moderate-to-high correlation confirms that while they share an underlying conceptual core—namely, a preference for group-based hierarchy over equality—they retain considerable independent variance ($55% – 80%$ unique variance), justifying their treatment as distinct psychological constructs.

Bifactor Modeling

When subjected to bifactor modeling, a strong general SDO factor accounts for the majority of the common variance (explained common variance, ECV > .60), supporting the calculation of a single overall composite SDO score when broad measurement is required. However, the specific orthogonal factors for SDO-D and SDO-E retain sufficient independent reliable variance to warrant independent subscale scoring, especially when investigating differential predictive targets (e.g., active violence versus policy obstruction).

Instrument / Measurement Tool

• Construct Measured: Social Dominance Orientation (preference for group-based social hierarchy and inequality).
• Subscales:
  • SDO-Dominance (SDO-D): Active, aggressive support for the dominance of superior groups over inferior groups (Items 1, 2, 3, 4, 5, 6, 7, 8).
  • SDO-Anti-egalitarianism (SDO-E): Opposition to group equality, resource redistribution, and egalitarian social systems (Items 9, 10, 11, 12, 13, 14, 15, 16).
• Total Number of Items: 16 items (in full version); an 8-item short form (SDO7(s)) also exists in published literature.
• Item Balancing: Perfectly balanced design containing 8 pro-trait items (1, 2, 3, 4, 9, 10, 11, 12) and 8 con-trait items (5, 6, 7, 8, 13, 14, 15, 16).
• Response Scale: 7-point Likert scale (1 = Strongly Oppose, 7 = Strongly Favor).
• Scoring Rules:
  • Reverse Scoring: Con-trait items (5, 6, 7, 8, 13, 14, 15, 16) must be reverse-scored prior to computation using the transformation: $\text{Item}_{\text{recoded}} = 8 – \text{Item}_{\text{raw}}$.
  • SDO-Dominance (SDO-D) Score: Calculated by averaging the responses to Items 1, 2, 3, 4 and reverse-coded Items 5, 6, 7, 8.
  • SDO-Anti-egalitarianism (SDO-E) Score: Calculated by averaging the responses to Items 9, 10, 11, 12 and reverse-coded Items 13, 14, 15, 16.
  • Overall Composite SDO7 Score: Calculated by computing the grand mean across all 16 items (after reverse scoring con-trait items). Higher scores indicate a greater preference for group-based hierarchy and inequality.
• Administration Time: Approximately 3 to 5 minutes.
• Format: Self-administered pencil-and-paper questionnaire or computerized online survey.

Permissions & Fee and Test Year

The Social Dominance Orientation Scale (SDO7) was published in 2015 in the Journal of Personality and Social Psychology by Arnold K. Ho and colleagues. The scale was developed with academic research support and is considered in the public domain for non-commercial academic, educational, and basic research applications.

No licensing fees or formal permissions are required for non-commercial empirical use by university scholars, students, or institutional researchers, provided that standard academic attribution is given to the original authors (Ho et al., 2015). Commercial entities, private consulting agencies, or corporate entities intending to integrate the SDO7 into proprietary psychological assessment suites or commercial software should consult the copyright policies of the American Psychological Association (APA) and the corresponding authors.

References

The following foundational publications provide theoretical, psychometric, and empirical background for the SDO7 scale:

• Duckitt, J. (2001). A dual-process cognitive-motivational model of ideology and prejudice. In M. P. Zanna (Ed.), Advances in Experimental Social Psychology (Vol. 33, pp. 41–113). Academic Press. https://doi.org/10.1016/S0065-2601(01)80004-6
• Ho, A. K., Sidanius, J., Kteily, N., Sheehy-Skeffington, J., Pratto, F., Henkel, K. E., Foels, R., & Stewart, A. L. (2015). The nature of social dominance orientation: Theorizing and measuring preferences for intergroup inequality using the new SDO7 scale. Journal of Personality and Social Psychology, 109(6), 1003–1028. https://doi.org/10.1037/pspi0000033
• Pratto, F., Sidanius, J., Stallworth, L. M., & Malle, B. F. (1994). Social dominance orientation: A personality variable predicting social and political attitudes. Journal of Personality and Social Psychology, 67(4), 741–763. https://doi.org/10.1037/0022-3514.67.4.741
• Sidanius, J., & Pratto, F. (1999). Social dominance: An intergroup theory of social hierarchy and oppression. Cambridge University Press. https://doi.org/10.1017/CBO9781139175043
• Sidanius, J., Pratto, F., van Laar, C., & Levin, S. (2004). Social dominance theory: Its agenda and method. Political Psychology, 25(6), 845–880. https://doi.org/10.1111/j.1467-9221.2004.00401.x

Items of the Scale