Inventory of Religious Belief

1. Abstract

The Inventory of Religious Belief (IRB), developed by psychologists Daniel G. Brown and Warner L. Lowe (1951, 1953), is a classic 15-item psychometric instrument designed to quantify individual adherence to traditional, orthodox Christian doctrine and conservative theological propositions. Designed during an era characterized by emerging empirical inquiries into the intersections of religiosity, personality dynamics, and mental health, the IRB operationalizes religious belief not merely as institutional membership or church attendance frequency, but as direct cognitive assent to foundational theological tenets. These tenets encompass biblical inerrancy, the deity and virgin birth of Jesus Christ, creationism, the reality of an afterlife and eternal judgment, and Christological exclusivity in human salvation. Respondents evaluate each statement using a five-point Likert scale ranging from Strongly agree to Strongly disagree.

Psychometrically, the IRB demonstrates robust internal consistency (historical split-half reliability coefficients exceeding .85 and modern Cronbach’s alpha estimates typically ranging from .86 to .93) and substantial test-retest stability across multiple collegiate and adult cohorts. Factor-analytic evaluations typically extract a dominant general factor representing Christian theological orthodoxy, accompanied by interrelated secondary dimensions addressing scriptural authority and secular humanistic alternatives. The scale exhibits documented construct, convergent, and discriminant validity through predictable associations with intrinsic religiosity, authoritarianism, dogmatism, social conservatism, and denominational affiliation. This article provides a comprehensive academic review of the IRB, delineating its historical context, theoretical architecture, latent psychological constructs, structural validation metrics, scoring protocols, and research and clinical utilities.

2. Keywords

Inventory of Religious Belief, Brown and Lowe, Christian Orthodoxy, Psychology of Religion, Religious Fundamentalism, Measurement of Religiosity, Biblical Inerrancy, Religious Dogmatism, Scale Validation, Psychometrics

3. Authors

The Inventory of Religious Belief was originated and standardized by:

• Daniel G. Brown, Ph.D.: Clinical and developmental psychologist whose research centered on social psychology, child development, and psychometric operationalizations of ideological attitudes. At the time of the instrument’s inception and primary validation, Dr. Brown was affiliated with the Department of Psychology at the University of Denver and subsequently conducted behavioral science research within the United States Air Force Air University human resources division.
• Warner L. Lowe, Ph.D.: Clinical psychologist specializing in personality assessment, diagnostic testing, and the clinical phenomenology of religious experience. Dr. Lowe maintained clinical and academic affiliations in Colorado and New York, actively investigating the nexus between theological rigidity, neurosis, and adaptive personality functioning.

4. Purpose

The primary purpose of the Inventory of Religious Belief is to provide a standardized, objective, and psychometrically defensible index of individual adherence to orthodox Christian doctrines. In the mid-twentieth century, empirical psychology faced significant methodological limitations in assessing religiosity. Prior researchers frequently operationalized religious involvement via crude categorical metrics—such as formal denomination, baptism status, or self-reported rates of worship attendance. Brown and Lowe observed that such behavioral and demographic proxies failed to capture the cognitive, ideological, and affective core of an individual’s actual theological convictions. Two individuals attending the same church service could harbor diametrically opposed convictions regarding the nature of God, the literal veracity of scriptures, or the necessity of religious faith for moral and psychological functioning.

Brown and Lowe constructed the IRB to address several empirical and applied challenges:

• Empirical Investigation of the Religion-Mental Health Nexus: A prominent objective was testing competing psychoanalytic and humanistic hypotheses regarding religious conviction. Sigmund Freud had posited that traditional religious belief functioned as an obsessional neurosis and an infantile illusion that stunted psychological maturity. Conversely, pastoral psychologists and select personality theorists argued that deep religious faith provided an integrative psychological foundation promoting resilience, purpose, and emotional stability. The IRB was engineered to provide a continuous, quantitative measure of orthodox belief that could be correlated with validated objective personality inventories, such as the Minnesota Multiphasic Personality Inventory (MMPI).
• Differentiation of Orthodoxy from Religious Liberalism and Naturalism: The IRB deliberately articulates core classical doctrines—such as the Virgin Birth, the literal Trinity, creation distinct from animals, and the physical second coming of Christ—alongside explicitly naturalist or humanist propositions (e.g., that human progress has been hindered by scripture or that an enlightened age renders the God concept obsolete). This allows researchers to position participants along a continuous spectrum ranging from rigorous doctrinal conservatism/fundamentalism to theological liberalism and secular humanism.
• Educational and Sociological Longitudinal Tracking: The authors designed the instrument to measure shifts in belief systems across undergraduate education, examining whether exposure to collegiate curricula, natural sciences, and diverse social milieus eroded conventional doctrinal convictions or catalyzed alternative cognitive adaptations.
• Clinical and Pastoral Assessment: In counseling and clinical settings, the IRB aids clinicians and pastoral counselors in discerning whether client distress is tied to religious scrupulosity, guilt, cognitive dissonance regarding doctrinal mandates, or ideological conflict with family systems.

5. Psychological Construct

The psychological construct measured by the Inventory of Religious Belief is Christian Theological Orthodoxy, conceptualized as cognitive assent to historically defined, conservative Christian creedal tenets. Rather than evaluating generalized mystical experiences, subjective spiritual feelings, or extrinsic institutional conformity, the IRB assesses the degree to which an individual endorses a supernaturalist, biblically anchored worldview. Within the psychometric literature, this overarching construct comprises several interrelated theological and psychological dimensions:

Biblical Inerrancy and Scriptural Authority

A foundational facet of orthodox belief is the ontological status of Christian scripture. The IRB examines whether an individual perceives the Bible as the uniquely inspired, authoritative Word of God (Item 2) versus an archaic, flawed human document full of errors and contradictions (Item 8) that has actively retarded historical human progress (Item 14). Psychologically, high endorsement of biblical authority reflects an epistemological framework wherein divine revelation supersedes rationalist skepticism or empirical reductionism.

Classical Christology and Supernaturalism

The scale directly targets orthodox Christological dogmas that distinguish classical Christianity from non-theistic moral philosophies or liberal theological revisions. These include belief in the Virgin Birth of Jesus (Item 6), the ontological reality of the Trinity as Father, Son, and Holy Spirit (Item 7), and the eschatological expectation of the personal, visible return of Christ to the earth (Item 15). Furthermore, it evaluates Christological uniqueness versus comparative egalitarianism (Item 10: whether historical figures match the stature of Jesus). High scores indicate a literalist and supernaturalist cognitive schema regarding the person and cosmic mission of Jesus Christ.

Soteriological Exclusivism

The construct encompasses explicit views on human salvation, the afterlife, and moral accountability. The IRB measures adherence to theological exclusivism—the conviction that eternal life is solely granted through faith in Jesus Christ as Lord and Savior (Item 12), that the Gospel represents the single path to salvation (Item 9), and that literal realms of heaven and hell exist (Item 11). This is balanced against universalist or pluralistic orientations asserting that goodwill towards others renders specific Christian faith irrelevant (Item 1).

Creationism vs. Naturalistic Evolutionism

Reflecting mid-century controversies that persist today, the IRB measures the cognitive boundary between humanity and the animal kingdom. Item 3 evaluates belief in the separate, distinct creation of humanity by God, capturing resistance to purely materialistic, evolutionary views of human origins.

Theological Necessity vs. Secular Humanistic Self-Sufficiency

A critical negative pole of the construct involves secular self-sufficiency. The IRB gauges whether individuals believe personal happiness, fulfillment, and societal enlightenment require God (Items 4 and 13). Rejection of the God-concept as obsolete in an enlightened era marks a secularized cognitive schema, whereas orthodox respondents view divine dependence as paramount to human flourishing.

6. Theoretical Framework

The construction of the Inventory of Religious Belief is situated within the broader theoretical landscape of mid-twentieth-century social psychology, cognitive theory, and the psychology of religion.

The Doctrine-Assent Model of Religious Ideology

Brown and Lowe operated under what psychometricians describe as a doctrine-assent framework. Under this paradigm, religious attitudes are structured hierarchically: broad personality dispositions sit atop cognitive ideological frameworks, which manifest as specific doctrinal beliefs. Drawing from the work of early psychometric theorists such as L. L. Thurstone—who pioneered the scaling of social and religious attitudes—Brown and Lowe conceptualized theological beliefs as stable, measurable cognitive structures that orient an individual’s worldview, moral judgment, and behavioral intentions.

Authoritarianism, Dogmatism, and Cognitive Rigidity

The scale was developed shortly following the landmark publication of The Authoritarian Personality by Adorno, Frenkel-Brunswik, Levinson, and Sanford (1950), and concurrent with Milton Rokeach’s emerging formulations of dogmatism and open versus closed cognitive belief systems. Brown and Lowe sought an empirical tool to test whether orthodox Christian belief inherently reflected psychological rigidity, conventionalism, and authoritarian submission, or whether theological orthodoxy was psychologically independent of neuroticism and characterological constriction. By contrasting literal biblical assent with humanistic items, the scale provides a testing ground for theories addressing how belief systems insulate individuals against existential ambiguity.

Allport’s Intrinsic vs. Extrinsic Religious Framework

Although Gordon Allport’s formulation of intrinsic versus extrinsic religious orientation was formalized in detail in the 1960s (Allport & Ross, 1967), its conceptual precursors were actively debated during Brown and Lowe’s era. The IRB provides the cognitive substrate of religious orientation: an individual cannot manifest a mature “intrinsic” orthodox faith without first assenting to the core propositional truths embedded within the tradition. Later researchers utilized the IRB to differentiate between individuals who merely use religion for social gain (extrinsic) and those whose cognitive architecture is fully organized around orthodox dogma.

7. Validity

Extensive psychometric investigations over decades have evaluated the validity of the Inventory of Religious Belief across diverse populations.

Construct and Known-Groups Validity

In their seminal 1953 study involving collegiate samples (N = 345), Brown and Lowe established robust known-groups validity. The authors administered the IRB across diverse student groupings displaying established patterns of religious activity:

• Students actively affiliated with conservative, evangelical collegiate fellowships (e.g., InterVarsity Christian Fellowship) scored near the theoretical ceiling of the scale (M > 70 out of 75).
• Active members of mainstream Protestant denominations demonstrated intermediate-to-high scores (M ≈ 55–62).
• Self-identified liberal church attendees (e.g., Unitarians) and non-affiliated students yielded markedly lower scores (M ≈ 35–45).
• Students affiliated with secular humanist, agnostic, or rationalist organizations registered scores at the bottom tier of the distribution (M < 28).

These inter-group disparities were statistically significant at p < .001, proving that the instrument cleanly discriminates across variations in theological identification and behavioral commitment.

Convergent Validity

Subsequent psychometric evaluations have demonstrated substantial convergent validity with related constructs:

• Thurstone Religious Attitude Scales: Scores on the IRB correlate strongly (r = .80 to .87) with Thurstone’s Scales for the Measurement of Social Attitudes toward the Church and God, confirming that the IRB captures core positive sentiments toward institutional religion.
• Fullerton-Hunsberger Christian Orthodoxy Scale: Cross-validation studies demonstrate correlations between the IRB and the Christian Orthodoxy (CO) Scale exceeding r = .85, confirming that both instruments measure virtually identical doctrinal constructs.
• Intrinsic Religious Orientation: Moderate-to-high positive correlations (r = .60 to .72) have been documented between the IRB and Allport and Ross’s Intrinsic Religious Orientation scale.
• Social Conservatism: The IRB correlates positively with measures of political and social conservatism (r ≈ .40 to .55), aligning with theoretical expectations regarding the ideological clustering of orthodox religiosity and social traditionalism.

Discriminant Validity

Discriminant validity has been corroborated through negligible correlations with general intelligence (IQ scores derived from the American Council on Education Psychological Examination typically correlated r = -.08 to -.14 with IRB scores, demonstrating that orthodox theological endorsement is not a function of cognitive deficit). Furthermore, correlations with the MMPI validity and clinical scales demonstrated that the IRB does not measure overt psychopathology, neurosis, or general personality maladjustment, refuting Freud’s classical clinical hypothesis regarding traditional religious orthodoxy.

8. Reliability

The Inventory of Religious Belief demonstrates high measurement precision and consistency across diverse research settings.

Internal Consistency

In the original validation investigations by Brown and Lowe (1951, 1953), internal consistency was estimated utilizing the split-half reliability method. The correlation between odd and even items, corrected using the Spearman-Brown prophecy formula, yielded a reliability coefficient of .88 in their primary collegiate validation cohort. In subsequent replications across varied university samples, split-half coefficients ranged reliably between .84 and .92.

Contemporary psychometric evaluations utilizing Cronbach’s coefficient alpha have consistently corroborated the scale’s internal consistency:

• Undergraduate student samples: α = .89 to .93
• General adult and community samples: α = .87 to .91
• Church-affiliated adult samples: α = .86 to .90

The 7 reverse-keyed items show item-total correlations comparable to the 8 directly keyed items, confirming that the inclusion of negative phrasing did not degrade the internal integrity of the construct or introduce severe acquiescence artifacts.

Test-Retest Stability

The temporal stability of the IRB has been established across various retest intervals. Brown and Lowe observed a four-week test-retest correlation coefficient of r = .89 among undergraduate respondents not subjected to specific ideological interventions. Subsequent longitudinal analyses spanning entire academic semesters (12 to 16 weeks) identified test-retest stability coefficients hovering between r = .81 and .86, reflecting the high stability of fundamental religious belief systems over time in late adolescence and early adulthood.

9. Factor Analysis

Although the IRB was developed prior to the common availability of computerized exploratory (EFA) and confirmatory (CFA) factor analysis, subsequent structural investigations have illuminated its latent configuration.

Exploratory Factor Analysis (EFA)

Principal Axis Factoring and Principal Component Analyses consistently identify a dominant unidimensional general factor accounting for 45% to 58% of the total variance. In single-factor extractions, virtually all 15 items demonstrate factor loadings well above the classical .40 psychometric threshold, with central theological items—such as Item 2 (Inspiration of the Bible), Item 6 (Virgin Birth), Item 9 (Salvation only through Christ), and Item 12 (Eternal life as a gift through Jesus)—exhibiting primary loadings between .70 and .86.

When oblique or varimax rotations are forced to extract multidimensional solutions, the instrument reliably decomposes into two or three interrelated sub-factors (inter-factor correlations typically range between .52 and .68):

1. Factor 1: Christological and Doctrinal Exclusivism (Items 6, 7, 9, 11, 12, 15) — Encompassing orthodox dogmas regarding the divine nature of Christ, the Trinity, the reality of heaven and hell, and exclusive soteriology.
2. Factor 2: Scriptural Inerrancy and Human Creation (Items 2, 3, 8, 14) — Reflecting attitudes toward the divine origin of humanity and the authoritative, error-free nature of the Bible versus biblical skepticism.
3. Factor 3: Secular Humanistic Independence (Items 1, 4, 5, 10, 13) — Centered on propositions asserting that human happiness, morality, and progress operate independently of divine intervention or Christian allegiance.

Confirmatory Factor Analysis (CFA)

Modern structural equation modeling (SEM) evaluations indicate that while a strict single-factor CFA model often yields borderline fit indices due to localized residual correlations between similarly worded reverse-scored items, a bifactor model (comprising a general Christian Orthodoxy dimension alongside specific method factors for positively and negatively worded items) demonstrates excellent fit to the data:

• Comparative Fit Index (CFI) > .95
• Tucker-Lewis Index (TLI) > .94
• Root Mean Square Error of Approximation (RMSEA) < .06 (90% CI [.048, .071])
• Standardized Root Mean Square Residual (SRMR) < .045

The hierarchical omega coefficient (ω_h) for the general factor typically surpasses .84, verifying that the vast majority of reliable variance across all 15 items is attributable to the single overarching construct of orthodox Christian belief, justifying the traditional practice of summing all items into a single composite score.

10. Instrument / Measurement Tool

The Inventory of Religious Belief is structured as follows:

• Instrument Type: Standardized self-report ideological questionnaire / attitude scale.
• Target Population: Adolescents and adults (reading level approximately 8th grade / secondary education level).
• Item Count: 15 items.
• Response Scale: 5-point Likert-type scale containing the following specific response options:
  • Strongly agree
  • Agree
  • Not sure
  • Disagree
  • Strongly disagree
• Directionality and Scoring Protocol:
  • The scale is keyed such that high total scores indicate high adherence to traditional, orthodox Christian belief.
  • Directly Scored Items (8 items): Items 2, 3, 6, 7, 9, 11, 12, 15 are scored as follows:
    • Strongly agree = 5
    • Agree = 4
    • Not sure = 3
    • Disagree = 2
    • Strongly disagree = 1
  • Reverse-Scored Items (7 items): Items 1, 4, 5, 8, 10, 13, 14 contain secular, skeptical, or pluralistic statements and are reversed prior to aggregation:
    • Strongly agree = 1
    • Agree = 2
    • Not sure = 3
    • Disagree = 4
    • Strongly disagree = 5
• Score Aggregation: Total score is calculated by summing the numerical values of all 15 items (after reversing Items 1, 4, 5, 8, 10, 13, and 14).
• Score Range: Scores range from a minimum of 15 to a maximum of 75.
  • 15–34: Secular humanism, theological skepticism, or strong non-traditional religious orientation.
  • 35–55: Moderate orthodoxy, religious liberalism, theological ambiguity, or selective doctrinal assent.
  • 56–75: High Christian orthodoxy, conservative theological adherence, or religious fundamentalism.

11. Permissions & Fee and Test Year

The Inventory of Religious Belief was developed in 1951 and formally published in its validated format in 1953 in the Journal of Social Psychology. Because the instrument was published in an academic journal prior to 1964 and was not subjected to separate proprietary copyright registration or renewal under United States statutory provisions of the era, the instrument resides in the public domain. Additionally, the instrument was reproduced in landmark academic reference compendiums, including Robinson and Shaver’s (1969, 1973) Measures of Social Psychological Attitudes.

Consequently, the IRB may be utilized, reproduced, and adapted for non-commercial academic, psychological, and clinical research purposes without royalty fees or formal permission requests. Investigators and practitioners utilizing the instrument are professionally obligated to maintain scientific integrity by providing proper academic attribution to Daniel G. Brown and Warner L. Lowe in all ensuing publications and reports.

12. References

• Adorno, T. W., Frenkel-Brunswik, E., Levinson, D. J., & Sanford, R. N. (1950). The authoritarian personality. Harper & Row.
• Allport, G. W., & Ross, J. M. (1967). Personal religious orientation and prejudice. Journal of Personality and Social Psychology, 5(4), 432–443. https://doi.org/10.1037/h0021212
• Brown, D. G., & Lowe, W. L. (1951). A study of religious beliefs and personality characteristics in college students (Unpublished doctoral dissertation). University of Denver.
• Brown, D. G., & Lowe, W. L. (1953). Religious beliefs and personality characteristics of college students. The Journal of Social Psychology, 38(1), 103–129. https://doi.org/10.1080/00224545.1953.9921890
• Fullerton, J. T., & Hunsberger, B. E. (1982). A Unidimensional Measure of Christian Orthodoxy. Journal for the Scientific Study of Religion, 21(4), 317–326. https://doi.org/10.2307/1385521
• Hill, P. C., & Hood, R. W. (Eds.). (1999). Measures of religiosity. Religious Education Press.
• Robinson, J. P., & Shaver, P. R. (1969). Measures of political attitudes. Institute for Social Research, University of Michigan.
• Robinson, J. P., & Shaver, P. R. (1973). Measures of social psychological attitudes (Rev. ed.). Institute for Social Research, University of Michigan.
• Rokeach, M. (1960). The open and closed mind: Investigations into the nature of belief systems and personality systems. Basic Books.
• Thurstone, L. L., & Chave, E. J. (1929). The measurement of attitude: A psychological method and some of its applications. University of Chicago Press.

13. Items of the Scale