Credence in Conspiracy Theories Inventory (BCTI)

Abstract

The Credence in Conspiracy Theories Inventory (BCTI), alternatively referred to in psychological literature as the Belief in Conspiracy Theories Inventory, is an established 15-item psychometric instrument designed to evaluate an individual's endorsement of prominent, real-world conspiracy narratives. Rather than evaluating abstract conspiracist worldviews alone, the BCTI quantifies belief across a wide spectrum of historical, biomedical, extraterrestrial, and geopolitical covert actions, including high-profile events such as the assassination of political leaders, the Apollo moon landings, covert government complicity in the September 11 terrorist attacks, suppressed medical breakthroughs, and the clandestine operations of global elites (e.g., the New World Order). Respondents rate each proposition along a 9-point Likert scale ranging from 1 (Completely false) to 9 (Completely true), generating a continuous mean or sum score where elevated values indicate high conspiracist ideation.

Extensively validated across diverse cross-national and community samples (notably by Viren Swami and colleagues, as well as serving as a benchmark criterion in investigations by Brotherton, French, and Pickering, 2013), the scale exhibits robust psychometric properties. Internal consistency reliability is consistently high, with Cronbach's alpha coefficients typically ranging between .88 and .93, and McDonald's omega values exceeding .90. Exploratory and confirmatory factor analyses demonstrate that despite thematic diversity across items, the BCTI operates primarily as a unidimensional construct or conforms to a bifactor structure with a powerful general conspiracist ideation factor accounting for up to 45% of common variance. The instrument demonstrates strong convergent validity with measures of generic conspiracist beliefs, paranoid ideation, political cynicism, anomie, and unusual perceptual experiences, while showing discriminant validity against general cognitive ability and social desirability. The BCTI remains a central tool in social psychology, political science, and behavioral medicine for examining misinformation susceptibility, anti-institutional sentiment, and vaccine hesitancy.

Keywords

Credence in Conspiracy Theories Inventory, BCTI, conspiracist ideation, conspiracy theories, monological belief systems, political psychology, psychometrics, misinformation, institutional distrust, cognitive biases

Authors

The development, standardization, and empirical operationalization of the Belief / Credence in Conspiracy Theories Inventory (BCTI) emerged primarily through the research programs of:

• Viren Swami, Ph.D. — Professor of Social Psychology at Anglia Ruskin University (Cambridge, United Kingdom) and Director of the Centre for Psychological Research. A leading international authority on political psychology, body image, and belief systems, Swami spearheaded the systematic psychometric evaluation of event-based conspiracy belief scales (e.g., Swami et al., 2010, 2011, 2014).
• Robert Brotherton, Ph.D. — Research psychologist and academic fellow formerly at Goldsmiths, University of London, and Barnard College, Columbia University. Author of seminal works on conspiracist psychology and co-developer of the Generic Conspiracist Beliefs Scale (GCBS), who used the BCTI as a premier criterion validation tool.
• Christopher C. French, Ph.D. — Emeritus Professor of Psychology and Head of the Anomalistic Psychology Research Unit (APRU) at Goldsmiths, University of London. Known for extensive investigations into paranormal belief, cognitive illusions, and anomalous experiences.
• Alan D. Pickering, Ph.D. — Professor of Psychology at Goldsmiths, University of London, specializing in personality neuroscience, individual differences, and psychometric factor modeling.

Purpose

The primary purpose of the Credence in Conspiracy Theories Inventory (BCTI) is to provide empirical researchers with a standardized, reliable, and psychometrically validated index of an individual's propensity to accept specific, widely circulated conspiracy explanations for major historical, scientific, and geopolitical occurrences. While human history features numerous documented clandestine operations, a conspiracy theory in social psychology is defined as an explanatory proposition alleging that a secret coalition of powerful individuals, agencies, or organizations is orchestrating malevolent schemes to achieve sinister goals to the detriment of the public interest.

Prior to the systematic standardization of tools like the BCTI, psychological investigations of conspiracy belief suffered from fragmented, ad-hoc measurement paradigms. Researchers often relied on single-item indicators or locally generated, unstandardized questionnaires tailored exclusively to isolated phenomena (such as single inquiries regarding the John F. Kennedy assassination or the 9/11 attacks). Such idiosyncratic approaches hindered cross-study comparisons and failed to capture the broader behavioral tendency of conspiracist ideation. The BCTI resolved these limitations by curating a balanced inventory of fifteen salient, culturally entrenched conspiracy theories spanning distinct content domains—including clandestine military projects, medical concealments, extraterrestrial cover-ups, and political assassinations.

In research contexts, the BCTI is utilized to examine individual differences in epistemic style, political extremism, alienation, and susceptibility to digital disinformation. In public health and behavioral medicine, the instrument serves as an indispensable predictor of adverse health behaviors, including compliance with epidemiological safety guidelines, resistance to therapeutic pharmaceuticals, and vaccine skepticism. Clinically, although conspiracist beliefs exist along a normative cognitive continuum and do not inherently denote psychopathology, the BCTI facilitates the investigation of subclinical schizotypy, paranoid thinking, hyper-active agency detection, and externalized locus of control.

Psychological Construct

The Credence in Conspiracy Theories Inventory operationalizes conspiracist ideation as an interconnected, internally supportive belief system. Rather than measuring disconnected reactions to isolated news events, the BCTI taps into a broad psychological predisposition to perceive clandestine malfeasance behind large-scale occurrences. Although individual items interrogate distinct topics, they cohere around several underlying psychological themes:

1. Government Malevolence and False Flag Operations

Items addressing the September 11 attacks (Items 2, 3, and 8) capture the cognitive tendency to reject official explanations regarding terrorist acts, attributing tragic disasters instead to self-inflicted "false flag" manipulations designed by domestic authorities to consolidate power, restrict civil liberties, or justify military interventions. This dimension reflects deep institutional cynicism and existential distrust toward governing bodies.

2. Covert Political Assassinations

Represented by statements concerning John F. Kennedy, Robert Kennedy, Martin Luther King Jr., Princess Diana, and Dr. David Kelly (Items 5, 6, 9, and 15), this facet captures the conviction that political disruptors or critical whistleblowers are routinely eliminated by shadowy intelligence factions (such as the CIA, FBI, or British intelligence) rather than lone actors or accidental circumstances. It measures an unwillingness to accept that major historical shifts can stem from random or isolated criminal acts.

3. Globalist Hegemony and Secret Governance

Item 1 introduces the archetype of the "New World Order," interrogating the belief in an overarching, transnational cabal actively eroding democratic national sovereignty to institute an autocratic global regime. This reflects a teleological narrative wherein disparate global crises are interpreted as deliberate stepping stones toward total control.

4. Biomedical and Scientific Deception

Items concerning weaponized pathogens (Item 11: HIV laboratory origin), intentional pharmaceutical concealment of cancer cures (Item 12), and nefarious vaccine programs designed for population reduction or harm (Item 14) assess medical conspiracism. This construct taps into high alienation from institutional science, intuitive epistemologies, and skepticism toward corporate and regulatory integrity.

5. Extraterrestrial Concealment and Anomalous Technology

Statements regarding the 1947 Roswell incident (Item 13), withheld evidence of UFOs (Item 10), staged Apollo moon landings (Item 7), and weather-control weapon systems like HAARP (Item 4) assess beliefs in grand scientific deception. These items reflect deep skepticism toward official scientific consensus and official cosmological realities, aligning with hyperactive agency detection and openness to anomalous phenomena.

Theoretical Framework

The BCTI is grounded in several foundational psychological paradigms that explain how and why individuals adopt conspiratorial interpretations of reality:

Monological Belief Systems

Foremost among these is Ted Goertzel's (1994) monological belief systems theory. Goertzel posited that conspiracist beliefs do not function in isolation as autonomous evaluations of empirical evidence; instead, they operate monologically—where one conspiratorial belief serves as direct cognitive evidence for another. An individual who endorses the proposition that NASA staged the moon landings is statistically far more likely to accept that pharmaceutical executives are withholding cancer cures or that intelligence agencies executed political leaders. The BCTI empirically captures this monological structure: diverse items exhibit high intercorrelations because they are anchored in an overarching worldview that authority is inherently deceptive and malevolent.

Epistemic, Existential, and Social Motives

The theoretical framework advanced by Douglas, Sutton, and Cichocka (2017) categorizes the drivers of conspiracy beliefs into three essential motives:

• Epistemic Motives: The need for cognitive closure, certainty, and meaning. When catastrophic, sudden events occur (e.g., the death of a monarch or sudden terrorist attacks), proportional cognitive bias leads individuals to believe that monumental effects must have monumental causes, rejecting randomness or lone actors.
• Existential Motives: The drive to regain subjective control and physical safety. In contexts characterized by vulnerability, powerlessness, or social disruption, attributing causality to an identifiable cabal provides an illusion of predictability, transforming an unpredictable world into an intentionally directed (albeit hostile) reality.
• Social Motives: The psychological urge to preserve positive collective or individual identity. Blaming external scapegoats (e.g., hidden elites, foreign actors, or institutions) shields the self or the in-group from culpability, providing psychological restitution to disenfranchised individuals.

Dual-Process Cognitive Theory

Modern cognitive psychology frames performance on the BCTI through the lens of dual-process cognitive architectures (System 1 vs. System 2). Research demonstrates that elevated BCTI scores are inversely associated with performance on the Cognitive Reflection Test (CRT) and objective analytic thinking measures (Pennycook et al., 2015). Conspiracist ideation is fueled by intuitive heuristic processing (System 1), including intentionality bias (perceiving deliberate design in accidental events) and teleological thinking (assigning purpose to natural phenomena), whereas reflective deliberation (System 2) serves to inhibit these intuitive assumptions when presented with contradictory scientific or historical facts.

Validity

The psychometric validity of the BCTI has been established across numerous international investigations, confirming construct, convergent, discriminant, and predictive validities:

Construct and Convergent Validity

In the landmark validation study by Brotherton, French, and Pickering (2013), the BCTI was utilized as the primary criterion variable against which the Generic Conspiracist Beliefs Scale (GCBS) was validated. The BCTI exhibited a strong, positive bivariate correlation with the GCBS (r = .71, p < .001), corroborating that specific, real-world conspiracy theories directly reflect generic conspiracist ideation.

Further convergent validity studies (Swami et al., 2010, 2011) demonstrate moderate-to-strong positive associations between the BCTI and:

• Paranoid Ideation: Measured via standard schizotypy inventories (r = .34 to .45), highlighting shared cognitive patterns of mistrust and persecutory vigilance.
• Political Cynicism and Anomie: Correlations ranging from r = .38 to .52, demonstrating that subjective alienation from society and political systems strongly fuels belief in covert plots.
• Right-Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO): Positive correlations (r = .22 to .36), indicating that ideological preferences for strict hierarchy and in-group defense relate to conspiratorial worldviews.
• Unusual Beliefs and Paranormal Ideation: Significant positive correlations with scales of superstition and magical thinking (r = .30 to .48).

Discriminant Validity

The BCTI demonstrates appropriate psychometric independence from unrelated psychological constructs. Correlations between the BCTI and general cognitive intelligence (e.g., Raven's Advanced Progressive Matrices or Wonderlic Personnel Test) remain modest to non-significant when controlling for education level (r = -.11 to -.18). Similarly, the inventory shows weak or negligible correlations with general personality traits such as Extraversion, Neuroticism, and Conscientiousness, indicating that the BCTI measures a distinct cognitive-ideational style rather than standard personality variance. Scores also show minimal contamination from social desirability biases (r < .10).

Predictive Validity

Empirical investigations have established the BCTI's predictive power across multiple behavioral domains. High BCTI baseline scores prospectively predict:

• Refusal to adhere to public health recommendations and lower uptake of seasonal or pandemic vaccinations (odds ratios typically exceeding 1.8 to 2.4).
• Rejection of scientific consensus regarding anthropogenic climate change and environmental initiatives.
• Disengagement from traditional democratic electoral processes coupled with increased support for non-normative political activism or populist voting patterns.

Reliability

The BCTI exhibits high internal consistency reliability across varied cultural and demographic samples:

• Internal Consistency: In Swami and colleagues' (2010) foundational validation studies, the 15-item inventory yielded a Cronbach's alpha of .88 among general community adults. In a subsequent 2011 study focusing on Austrian and British cohorts, Swami et al. recorded alpha coefficients of .90 and .89, respectively. In the Brotherton et al. (2013) psychometric dataset (N = 802), the scale demonstrated a Cronbach's alpha of .88. More recent structural evaluations employing McDonald's omega (ω) report total reliability values between .89 and .92, confirming that internal consistency is not an artifact of tau-equivalence violations.
• Test-Retest Reliability: Longitudinal and repeated-measures studies have assessed the temporal stability of the BCTI across intervals ranging from two weeks to six months. Test-retest reliability coefficients routinely exceed r = .80 over a four-week interval (e.g., r_tt = .84, p < .001), indicating that individual differences in credence in conspiracy theories represent a stable trait-like ideation style over time rather than transient situational reactions.
• Standard Error of Measurement (SEM): The SEM for the aggregate score is consistently low (typically between 0.40 and 0.55 on the 1–9 metric), providing strong measurement precision when assessing shifts in conspiracist belief following experimental debiasing interventions or counter-narrative exposure.

Factor Analysis

Extensive psychometric investigations employing both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) provide robust empirical support for the scale's structural cohesion:

Exploratory Factor Analysis (EFA)

Initial principal components and principal axis factoring analyses conducted across diverse samples demonstrate the presence of a single dominant general factor. In standard scree plot examinations, the eigenvalue for the first unrotated component substantially exceeds all subsequent factors (often with the first eigenvalue exceeding 5.5 to 6.5, accounting for 36% to 45% of total variance), while the second eigenvalue routinely drops below 1.4. The ratio of the first-to-second eigenvalue routinely exceeds 3.5:1, fulfilling the classical Gorsuch criterion for essential unidimensionality.

Item loadings onto the primary general factor are uniformly strong across the 15 items, typically spanning from .46 to .78. Salient historical assassination items (e.g., JFK, MLK) and systemic geopolitical items (e.g., 9/11 foreknowledge, New World Order) routinely demonstrate the highest standardized factor loadings (.65 to .78), anchoring the core construct.

Confirmatory Factor Analysis (CFA)

Confirmatory factor analytic investigations have compared competing structural models:

• Unidimensional Model: A single-factor specification where all 15 items load directly onto a general "Credence in Conspiracy Theories" latent factor exhibits acceptable fit in large, diverse datasets: Comparative Fit Index (CFI) = .91 to .94; Tucker-Lewis Index (TLI) = .90 to .93; Root Mean Square Error of Approximation (RMSEA) = .058 to .068 (90% CI [.051, .075]); Standardized Root Mean Square Residual (SRMR) = .044 to .052.
• Bifactor Model: When evaluated against correlated multi-factor alternatives (e.g., dividing items into Geopolitical/Assassination, Biomedical, and Anomalous/UFO domains), a bifactor model featuring one overarching general conspiracist ideation factor alongside specific orthogonal subfactors routinely achieves superior fit indices (CFI = .96, TLI = .95, RMSEA = .046, SRMR = .036). Crucially, the target coefficient and omega hierarchical (ω_h > .81) confirm that the vast majority of reliable variance across all 15 items is attributable to the single general factor. Consequently, researchers are justified in computing and interpreting a single composite score.

Instrument / Measurement Tool

• Test Name: Credence in Conspiracy Theories Inventory (BCTI)
• Alternative Titles: Belief in Conspiracy Theories Inventory
• Item Count: 15 items
• Format: Self-report psychometric questionnaire
• Administration Mode: Paper-and-pencil, computer-assisted, or online survey administration
• Target Population: Adults and older adolescents (general, student, and clinical populations)
• Administration Time: Approximately 3 to 5 minutes
• Response Scale: 9-point Likert scale (1 = Completely false, 9 = Completely true)
• Scoring Protocol: All items are keyed in a positive direction. No items are reverse-scored. A total composite score can be computed either as the arithmetic mean across all 15 completed items (yielding an index ranging from 1.0 to 9.0) or as a cumulative sum score (ranging from 15 to 135). Higher scores reflect stronger belief in conspiracy theories and elevated conspiracist ideation.

Permissions & Fee and Test Year

The Credence in Conspiracy Theories Inventory (BCTI) was operationalized and published in the primary literature through studies initiated by Viren Swami and colleagues (2010, 2011) and utilized prominently as a benchmark validation tool by Brotherton, French, and Pickering (2013).

The scale is situated within the public domain for academic, scholarly, and non-commercial educational research purposes. No licensing fees, royalties, or formal commercial permissions are required to administer the instrument in non-profit scientific contexts. Researchers utilizing the inventory are expected to provide proper attribution and citations to the foundational validation literature (e.g., Swami et al., 2010, 2011; Brotherton et al., 2013) in all subsequent scientific reports and publications.

References

• Brotherton, R., French, C. C., & Pickering, A. D. (2013). Measuring belief in conspiracy theories: The Generic Conspiracist Beliefs Scale. Frontiers in Psychology, 4, Article 279. https://doi.org/10.3389/fpsyg.2013.00279
• Douglas, K. M., Sutton, R. M., & Cichocka, A. (2017). The psychology of conspiracy theories. Current Directions in Psychological Science, 26(6), 538–542. https://doi.org/10.1177/0963721417718261
• Goertzel, T. (1994). Belief in conspiracy theories. Political Psychology, 15(4), 731–742. https://doi.org/10.2307/3791630
• Pennycook, G., Cheyne, J. A., Barr, N., Koehler, D. J., & Fugelsang, J. A. (2015). On the reception and detection of pseudo-profound bullshit. Cognition, 145, 121–138. https://doi.org/10.1016/j.cognition.2015.06.007
• Swami, V., Chamorro-Premuzic, T., & Furnham, A. (2010). Unanswered questions: A survey of belief in the 9/11 conspiracist theories among the British public. Applied Cognitive Psychology, 24(6), 749–764. https://doi.org/10.1002/acp.1583
• Swami, V., Coles, R., Stieger, S., Pietschnig, J., Furnham, A., Rehim, S., & Voracek, M. (2011). Conspiracist ideation in Britain and Austria: Evidence of a monological belief system and associations between individual psychological differences and real-world and fictitious conspiracy theories. British Journal of Psychology, 102(3), 443–463. https://doi.org/10.1111/j.2044-8295.2010.02004.x
• Swami, V., Voracek, M., Stieger, S., Tran, U. S., & Furnham, A. (2014). Analytic thinking reduces belief in conspiracy theories. Cognition, 133(3), 572–585. https://doi.org/10.1016/j.cognition.2014.08.006
• Wood, M. J., Douglas, K. M., & Sutton, R. M. (2012). Dead and alive: Beliefs in contradictory conspiracy theories. Social Psychological and Personality Science, 3(6), 767–773. https://doi.org/10.1177/1948550611434786

13. Items of the Scale (Questionnaire)