Credibility (Expertise) (CREDEXP)

1. Abstract

The Credibility (Expertise) (CREDEXP) scale is a specialized, four-item psychometric subscale developed by Stephen J. Newell and Ronald E. Goldsmith (2001) as an integral dimension of their foundational Corporate Credibility Scale. Designed to operationalize the degree to which an organization or corporate entity is perceived by stakeholders, consumers, and the public as experienced, technically competent, proficient, and authoritative within its operational domain, the CREDEXP subscale addresses a critical gap in organizational measurement. Rooted in classical source credibility theory and consumer psychology, the instrument isolates technical competence from affective or moral judgments (such as corporate trustworthiness). Administered via a standard seven-point Likert-type response format ranging from 1 (“Strongly Disagree”) to 7 (“Strongly Agree”), the four items assess institutional track record, operational capability, subject-matter expertise, and experiential deficits via one reverse-coded item.

Extensive psychometric evaluations conducted across diverse consumer samples indicate that the CREDEXP scale exhibits exceptional psychometric stability. Confirmatory factor analyses (CFA) consistently demonstrate robust single-factor dimensionality for the subscale and clear discriminant divergence from the companion Trustworthiness (CREDTRU) dimension, with structural equation modeling fit indices frequently satisfying stringent thresholds (CFI > .95, RMSEA < .06). Reliability metrics, including Cronbach’s alpha coefficients typically exceeding α = .88 and composite reliability values well above the .70 criterion, affirm strong internal consistency. Convergent validity is evidenced through substantial factor loadings (> .75) and average variance extracted (AVE) surpassing .60. Predictive validity analyses show that perceived corporate expertise significantly influences consumer attitude toward the advertisement ($A_{ad}$), attitude toward the brand ($A_b$), corporate reputation, and behavioral purchase intentions ($PI$). Consequently, CREDEXP serves as an authoritative, parsimonious instrument in marketing science, strategic communication, organizational behavior, and public relations research.

2. Keywords

Corporate Credibility, Perceived Expertise, Source Credibility Theory, Psychometrics, Newell and Goldsmith, Scale Validation, Brand Equity, Organizational Competence, Structural Equation Modeling, Persuasion Knowledge

3. Authors

The CREDEXP scale was conceptualized, operationalized, and psychometrically validated by:

• Stephen J. Newell, Ph.D. — Professor of Marketing and Associate Dean of Operations and Undergraduate Programs at the Haworth College of Business, Western Michigan University, Kalamazoo, Michigan, United States. Dr. Newell’s research focuses on corporate communication, source credibility, sales management, and organizational marketing strategy.
• Ronald E. Goldsmith, Ph.D. — Richard M. Baker Emeritus Professor of Marketing at the College of Business, Florida State University, Tallahassee, Florida, United States. A prominent psychometrician and consumer behaviorist, Dr. Goldsmith has authored seminal research on scale development, consumer innovativeness, market mavenism, and structural equation modeling in business research.

Scholarly correspondence regarding the original scale development can be directed to the Department of Marketing, Western Michigan University, or via archival academic records indexed in the Journal of Business Research.

4. Purpose

In modern market environments characterized by information asymmetry, product proliferation, and hyper-competitive organizational landscapes, stakeholders must routinely evaluate corporate messages without having complete technical knowledge of the firm’s manufacturing processes, operational algorithms, or supply chain integrity. Consequently, stakeholders rely on cognitive heuristics and reputational signals to evaluate corporate claims. The primary purpose of the Credibility (Expertise) (CREDEXP) scale is to furnish researchers, corporate strategists, and industrial psychologists with a reliable, empirically validated, and highly parsimonious measurement tool that captures perceived corporate expertise independently from confounding social, emotional, or moral evaluations.

Historically, research examining source credibility originated within interpersonal communication frameworks (e.g., public speaking, political rhetoric, and individual spokesperson endorsement). However, transferring these interpersonal dimensions directly to complex corporate entities created considerable theoretical and methodological ambiguity. Corporate bodies possess collective institutional identities that operate differently from human spokespersons. Newell and Goldsmith recognized that while a firm might be viewed as benevolent or ethical (trustworthy), it may simultaneously be perceived as technologically outmoded, operationally clumsy, or amateurish (lacking expertise). Conversely, a multinational monopoly might be recognized as exceptionally capable, technologically sophisticated, and industrially expert, despite severe public skepticism regarding its motives or honesty. The CREDEXP scale was specifically engineered to measure this cognitive, ability-based dimension of corporate credibility.

In applied and empirical contexts, the CREDEXP instrument serves multiple critical functions:

• Strategic Marketing and Brand Positioning: Allows brand managers to quantitatively measure baseline consumer perceptions regarding whether a company is recognized as an authoritative, competent leader in its category, especially prior to and following major product launches or rebranding initiatives.
• Corporate Crisis Management and Recovery: Enables organizational psychologists and public relations analysts to diagnose whether a corporate crisis (e.g., an industrial safety breakdown, algorithmic failure, or financial misstatement) has eroded consumer confidence in the firm’s technical competence versus its institutional morality, allowing for targeted remediation.
• Empirical Persuasion Research: Serves as a diagnostic covariate or mediator in psychological experiments examining advertising effectiveness, corporate advocacy, consumer resistance, and the boundary conditions of the Elaboration Likelihood Model (ELM).
• B2B and Stakeholder Relationship Audits: Evaluates institutional credibility among institutional investors, supply chain partners, and regulatory agencies where perceived technical qualifications and track records dictate high-stakes capital allocations.

5. Psychological Construct

The construct measured by the CREDEXP scale is Perceived Corporate Expertise. Psychometrically defined, perceived corporate expertise represents the extent to which a focal organization is judged by an observer as possessing the specialized knowledge, technical competencies, accumulated experience, operational skills, and intellectual capabilities necessary to consistently fulfill its stated claims, deliver high-quality outputs, and solve complex domain-specific problems. Unlike objective corporate competence—which might be quantified using patent counts, balance sheet liquidity, ISO certifications, or manufacturing defect rates—perceived corporate expertise is an evaluative, perceptual construct situated within the cognitive psychology of the perceiver.

In the tripartite conceptualization of attitudes (cognitive, affective, and conative), perceived expertise is fundamentally cognitive. It reflects propositional beliefs held by an individual concerning a firm’s ability-related attributes. These beliefs crystallize through direct personal interactions (e.g., past product usage), indirect social communications (e.g., word-of-mouth, journalism, independent reviews), and firm-controlled signaling (e.g., corporate advertising, technical whitepapers, and public leadership disclosures). When individuals process messages from a corporate source, the cognitive dimension of expertise serves as an anchor determining the source’s informational authority.

Within Newell and Goldsmith’s (2001) conceptual model, corporate credibility is bifurcated into two distinct yet correlated latent constructs:

1. Corporate Expertise (CREDEXP): The perceived ability, skill, and knowledge of the organization to execute its trade, innovate, and provide superior market offerings.
2. Corporate Trustworthiness (CREDTRU): The perceived honesty, integrity, benevolence, and moral reliability of the organization in its stakeholder dealings.

To fully appreciate the conceptual depth of CREDEXP, it must be decomposed into its three constitutive indicators:

• Accumulated Experience: Reflects the temporal and operational seasoning of the enterprise. Stakeholders view longevity, operational history, and market endurance as proxies for institutional learning, crisis survival, and tacit organizational knowledge. An organization high in perceived experience is believed to have navigated diverse market conditions and refined its operational frameworks over time.
• Domain-Specific Skill: Measures the perceived craftsmanship, execution proficiency, and technical craftsmanship of the firm’s workforce and structural systems. Skill captures the active execution of knowledge—how well the firm translates theoretical mastery into reliable, defect-free products, seamless logistics, and responsive services.
• Specialized Expertise: Captures the depth of the company’s intellectual and technological capital. This facet encompasses advanced technical competencies, research and development prowess, institutional authority, and superior know-how relative to industry peers.

Crucially, CREDEXP treats corporate expertise as a unidimensional sub-construct within the broader multi-factor framework of corporate reputation. While an entity may demonstrate varying degrees of expertise across disparate operational divisions (e.g., an electronics conglomerate possessing high expertise in displays but low expertise in audio engineering), the CREDEXP scale measures the generalized, top-of-mind gestalt perception of competence that consumers assign to the overarching corporate brand.

6. Theoretical Framework

The conceptual foundation of the CREDEXP scale rests at the intersection of classical communication theory, cognitive information processing, and economic signaling paradigms. The development of the scale synthesized several foundational theoretical models:

The Yale Communication Program and Source Credibility Theory

The earliest formal psychometric examinations of credibility emerged from the Yale Communication and Attitude Change Program directed by Carl Hovland and colleagues (Hovland, Janis, & Kelley, 1953; Hovland & Weiss, 1951). Investigating social persuasion, Hovland identified two fundamental pillars that determine whether an audience accepts a communicator’s message: expertness (the communicator’s perceived qualification to make valid assertions) and trustworthiness (the audience’s confidence that the communicator intends to communicate valid assertions without bias or deception). Subsequent interpersonal research by McCroskey and Jenson (1975) expanded these dimensions into multidimensional arrays. Newell and Goldsmith (2001) systematically established that despite the proliferation of complex multidimensional models in speech communication, corporate communication robustly condenses back into Hovland’s parsimonious two-factor paradigm: expertise and trustworthiness.

Signaling Theory under Information Asymmetry

Under Signaling Theory (Spence, 1973; Kirmani & Rao, 2000), markets are characterized by asymmetric information: sellers possess comprehensive knowledge regarding the true quality of their offerings, whereas buyers possess incomplete, imperfect information. To alleviate market failure caused by adverse selection (Akerlof, 1970), high-quality organizations deploy credible, cost-intensive signals to demonstrate their true underlying capabilities. A firm’s accumulated expertise represents an unobservable, highly valuable asset. By cultivating perceived corporate expertise, an enterprise projects an unobservable quality signal that reduces perceived purchase risk for consumers. The CREDEXP scale captures the empirical efficacy of these corporate signals in elevating consumer subjective confidence.

Dual-Process Models of Persuasion: The Elaboration Likelihood Model (ELM)

According to the Elaboration Likelihood Model (Petty & Cacioppo, 1986), persuasion occurs along two distinct processing routes: the central route and the peripheral route. The functional role of source expertise dynamically fluctuates depending on an individual’s cognitive motivation and ability to scrutinize message arguments:

• Low Elaboration (Peripheral Route): When consumers lack the motivation, involvement, or cognitive capacity to analyze complex product claims, perceived source expertise serves as a cognitive heuristic (“Experts can be trusted; therefore, this claim must be accurate”). In this mode, high CREDEXP scores trigger rapid acceptance of corporate advertising without systematic argument evaluation.
• High Elaboration (Central Route): When consumers are highly motivated and deeply involved, perceived corporate expertise does not simply act as a peripheral cue. Instead, it can bias cognitive processing, direct positive cognitive elaborations, or serve as a persuasive argument in itself (e.g., verifying that the firm possess the technological prowess to support its engineering claims).

Corporate Reputation and Brand Equity Frameworks

In modern strategic marketing, CREDEXP interfaces with corporate brand equity models (Keller, 1993; Aaker, 1996) and the corporate reputation framework (Fombrun, 1996). Corporate expertise forms the cognitive foundation of organizational legitimacy and brand stature. Without demonstrable expertise, brand equity remains vulnerable to competitive obsolescence, whereas high perceived expertise erects sustainable psychological barriers to entry.

7. Validity

The psychometric validation of the CREDEXP scale by Newell and Goldsmith (2001) followed rigorous, multi-stage construct validation protocols aligned with psychometric standards recommended by Churchill (1979) and Gerbing and Anderson (1988).

Content and Face Validity

Content validity was established during initial item generation through an exhaustive review of the extant literature on communicator credibility, advertiser credibility, and organizational reputation. An initial pool of potential items was evaluated by expert panels comprising marketing professors and psychometricians. Judges assessed each item for clarity, domain representativeness, semantic redundancy, and construct purity. Items that conflated corporate expertise with general admiration, financial size, or moral integrity were eliminated, resulting in a refined set of candidate items explicitly mapping onto skill, experience, and domain knowledge.

Construct and Factorial Validity

Factorial validity was established across independent data collections utilizing both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). In an initial development sample ($N = 197$), principal components and principal axis factoring with oblique rotation yielded a clean two-factor solution corresponding directly to Corporate Expertise and Corporate Trustworthiness. The four CREDEXP items loaded substantially on their hypothesized latent construct (loadings ranging from .76 to .91) with negligible cross-loadings on the Trustworthiness factor (< .20). Subsequent CFA on an independent validation sample ($N = 372$) confirmed that the two-factor model provided a superior fit over a single-factor “generalized credibility” model, establishing structural construct validity.

Convergent Validity

Convergent validity evaluates the extent to which the indicators of a latent construct share a high proportion of common variance. In Newell and Goldsmith’s (2001) structural models, all standardized factor loadings for the four CREDEXP items were statistically significant ($p < .001$) and exceeded the recognized threshold of .70. The Average Variance Extracted (AVE) for the CREDEXP subscale consistently surpassed the .50 benchmark (typically exceeding .65), confirming that the latent construct explains far more variance in its observed indicators than measurement error does.

Discriminant Validity

A central psychometric objective of Newell and Goldsmith was ensuring that Perceived Expertise was empirically distinct from Perceived Trustworthiness. Discriminant validity was empirically substantiated through several diagnostic tests:

• Chi-Square Difference Testing: A constrained CFA model (where the correlation between CREDEXP and CREDTRU was fixed to 1.0) was statistically compared against an unconstrained model (where the correlation was freely estimated). The unconstrained model exhibited a statistically significant reduction in chi-square ($\Delta \chi^2$, $p < .001$), demonstrating that the two dimensions are non-redundant.
• Fornell-Larcker Criterion: The AVE of CREDEXP exceeded the squared correlation between CREDEXP and CREDTRU ($\phi^2$), confirming that the construct shares more variance with its own indicators than with the companion dimension.

Criterion-Related and Predictive Validity

The utility of any psychometric tool hinges on its ability to forecast theoretically linked outcomes. Newell and Goldsmith (2001) tested the predictive efficacy of CREDEXP within a structural equation model evaluating consumer responses to advertisements. CREDEXP accounted for significant, direct proportions of variance in:

• Attitude Toward the Advertisement ($A_{ad}$): Perceptions of high corporate expertise positively elevated evaluations of ad informativeness and aesthetic credibility ($eta pprox .25$ to $.35$, $p < .01$).
• Attitude Toward the Brand ($A_b$): Mediated partially by $A_{ad}$ and partially through direct cognitive appraisal, CREDEXP significantly predicted overall brand evaluations ($eta pprox .30$ to $.45$, $p < .001$).
• Purchase Intentions ($PI$): Downstream structural paths established that higher perceived expertise significantly bolstered consumer willingness to purchase corporate products, especially in complex, high-involvement service and technological categories.

8. Reliability

The internal consistency and measurement stability of the CREDEXP scale have been documented across numerous studies. Psychometric theory dictates that reliable instruments minimize random measurement error, thereby yielding consistent scores across repeated administrations and within-scale items.

Internal Consistency Metrics

In the foundational scale development studies conducted by Newell and Goldsmith (2001), the CREDEXP subscale demonstrated internal consistency metrics that comfortably exceed established psychometric benchmarks:

• Study 1 (Initial Scale Development, $N = 197$): The four-item CREDEXP subscale exhibited a Cronbach’s alpha of $lpha = .89$. Item-total correlations ranged from .72 to .81, indicating that all four items contributed substantially to scale homogeneity.
• Study 2 (Scale Validation Sample, $N = 372$): The internal consistency remained robust with a Cronbach’s alpha of $lpha = .91$. The calculated Composite Reliability ($CR$) derived from CFA standardized parameters exceeded .90, confirming that parameter estimates were not an artifact of sample-specific variance.
• Study 3 (Nomological Network Re-Testing, $N = 215$): Cronbach’s alpha was observed at $lpha = .88$, demonstrating consistency across varying stimulus contexts (evaluating fictitious vs. established corporate entities).

Replication and Cross-Cultural Reliability

Subsequent independent studies in consumer behavior, service marketing, and corporate communications have repeatedly confirmed the scale’s high internal consistency. Replications across diverse industries—ranging from airline carriers and telecommunications providers to financial institutions and pharmaceutical manufacturers—consistently report Cronbach’s alphas between .85 and .93. Cross-cultural adaptations of the scale (translated into Spanish, German, Chinese, and Korean) have maintained internal consistency reliability estimates well above the standard .70 or .80 academic research thresholds.

Scale Parsimony and Error Variance

The four-item structure achieves an optimal balance between reliability and brevity. With an Average Variance Extracted (AVE) routinely above .65, over 65% of the variance captured by the measure reflects true score construct variance rather than idiosyncratic item error. The inclusion of one negatively worded (reverse-scored) item (“[Company] does not have much experience”) prevents systematic acquiescence response bias without introducing substantial method-factor artifact, provided participants are attentive.

9. Factor Analysis

The structural composition of the CREDEXP scale was isolated and confirmed using exploratory and confirmatory factor analytic procedures.

Exploratory Factor Analysis (EFA)

During the initial derivation phase, candidate items reflecting corporate credibility were subjected to common factor analysis (principal axis factoring) with both orthogonal (Varimax) and oblique (Promax) rotations to allow for expected inter-factor correlations between expertise and trustworthiness. Kaiser-Meyer-Olkin (KMO) measures of sampling adequacy were consistently observed above .85, and Bartlett’s Test of Sphericity yielded significant results ($\chi^2, p < .001$), confirming data factorability.

The eigenvalues-greater-than-one (Kaiser) criterion, paired with Cattell’s scree plot analysis, distinctly identified a two-factor latent structure. The first factor accounted for the majority of the common variance, representing Corporate Trustworthiness, while the second factor represented Corporate Expertise (or vice versa, depending on the sample stimulus). The four items designated for the CREDEXP subscale loaded heavily on their intended latent dimension:

Item Description	Target Factor Loading (CREDEXP)	Cross-Factor Loading (CREDTRU)
1. [Company] has a great amount of experience.	.84	.12
2. [Company] is skilled in what they do.	.88	.18
3. [Company] has great expertise.	.90	.15
4. [Company] does not have much experience. (R)	.76	-.08

Confirmatory Factor Analysis (CFA)

To substantiate the stability of the measurement model, Confirmatory Factor Analysis via maximum likelihood estimation was performed on validation data ($N = 372$). The hypothesized two-factor oblique measurement model—comprising the 4-item CREDEXP subscale and the 4-item CREDTRU subscale—was subjected to rigorous goodness-of-fit evaluation:

• Chi-Square / Degrees of Freedom Ratio ($\chi^2 / df$): The two-factor model demonstrated an acceptable ratio typically below 2.50, indicating good model parsimony.
• Comparative Fit Index (CFI): The CFI was estimated at $.97$, significantly exceeding the established $.95$ cutoff for exemplary model fit (Hu & Bentler, 1999).
• Tucker-Lewis Index (TLI / NNFI): Estimated at $.96$, confirming substantial improvement over the baseline independence model.
• Root Mean Square Error of Approximation (RMSEA): Observed at $.051$ with a 90% confidence interval ranging from $.038$ to $.065$, demonstrating close approximate fit to the population covariance matrix.
• Standardized Root Mean Square Residual (SRMR): Estimated at $.034$, well below the critical $.08$ ceiling.

When researchers contrasted this two-factor model against an alternate, nested, unidimensional model (in which all eight credibility items were constrained to load onto a single omnibus “Credibility” factor), the single-factor model exhibited poor fit ($ ext{CFI} < .80$,$ ext{RMSEA} > .13$). This structural breakdown confirmed that perceived corporate expertise is an autonomous psychological dimension that cannot be subsumed under general corporate goodwill.

10. Instrument / Measurement Tool

The operational specifications of the CREDEXP measurement tool are detailed below:

• Instrument Designation: Credibility (Expertise) Subscale (CREDEXP), constituent of the Corporate Credibility Scale.
• Primary Construct Measured: Perceived Corporate Expertise (technical proficiency, operational skill, industry knowledge, and organizational experience).
• Administration Format: Standardized paper-and-pencil inventory or computer-assisted self-administered questionnaire (web-based survey).
• Respondent Population: Adult consumers, corporate stakeholders, industrial buyers, institutional investors, or organizational employees evaluating a target company.
• Total Item Count: 4 items (3 positively keyed, 1 negatively keyed).
• Item Format: Declarative psychometric statements referencing a focal company name (denoted as “[Company]” in the scale inventory).
• Response Scale: 7-point Likert response format anchored from:
  • 1 = Strongly Disagree
  • 2 = Disagree
  • 3 = Somewhat Disagree
  • 4 = Neither Agree nor Disagree (Neutral)
  • 5 = Somewhat Agree
  • 6 = Agree
  • 7 = Strongly Agree
• Scoring Protocol:
  • Reverse Coding: Prior to computing scale scores, Item 4 (“[Company] does not have much experience”) must be reversed. On a 1-to-7 metric, this is executed via the formula: $ ext{Item4}_{ ext{recoded}} = 8 – ext{Item4}_{ ext{original}}$.
  • Composite Score Calculation: A mean composite score is computed by summing the values of Items 1, 2, 3, and the recoded Item 4, and dividing by 4 ($ ext{CREDEXP} = rac{ ext{Item1} + ext{Item2} + ext{Item3} + ext{Item4}_{ ext{recoded}}}{4}$). Alternatively, a summed raw score ranging from 4 to 28 may be used in specific path-analytic contexts.
  • Interpretation: Higher scores denote higher levels of perceived corporate technical expertise, knowledge, and operational skill. Scores approaching 7 represent consummate perceived industry authority; scores clustering around 4 represent perceptual neutrality or ambiguous consumer knowledge; scores descending toward 1 indicate marked perceptions of institutional incompetence or inexperience.
• Completion Time: Approximately 1 to 2 minutes for the CREDEXP subscale alone; approximately 3 to 4 minutes when administered alongside the sister CREDTRU (Trustworthiness) subscale.

11. Permissions & Fee and Test Year

The Credibility (Expertise) (CREDEXP) subscale was formally published in 2001 within the Journal of Business Research (Volume 52, Issue 3). The copyright for the academic article and original publication is held by Elsevier Science Inc.

Licensing and Terms of Use:

• Non-Commercial Academic Research: In accordance with standard academic conventions and fair-use doctrines, researchers, graduate students, and non-profit academic institutions may utilize the four CREDEXP items for non-commercial scholarly inquiries, empirical theses, and educational activities without direct royalty fees, provided appropriate bibliographic attribution is given to the original authors (Newell & Goldsmith, 2001).
• Commercial and Proprietary Applications: Commercial enterprises, consulting firms, market research agencies, and proprietary brand tracking services intending to incorporate the scale into commercial audit batteries or fee-for-service diagnostics should consult the RightsLink platform via Elsevier to determine formal copyright licensing requirements.

12. References

The theoretical and empirical foundations of the CREDEXP scale are anchored in the following literature:

• Aaker, D. A. (1996). Building strong brands. Free Press.
• Akerlof, G. A. (1970). The market for “lemons”: Quality uncertainty and the market mechanism. Quarterly Journal of Economics, 84(3), 488–500. https://doi.org/10.2307/1879431
• Churchill, G. A., Jr. (1979). A paradigm for developing better measures of marketing constructs. Journal of Marketing Research, 16(1), 64–73. https://doi.org/10.1177/002224377901600110
• Fombrun, C. J. (1996). Reputation: Realizing value from the corporate image. Harvard Business School Press.
• Gerbing, D. W., & Anderson, J. C. (1988). An updated paradigm for scale development incorporating unidimensionality and its assessment. Journal of Marketing Research, 25(2), 186–192. https://doi.org/10.1177/002224378802500207
• Hovland, C. I., Janis, I. L., & Kelley, H. H. (1953). Communication and persuasion: Psychological studies of opinion change. Yale University Press.
• Hovland, C. I., & Weiss, W. (1951). The influence of source credibility on communication effectiveness. Public Opinion Quarterly, 15(4), 635–650. https://doi.org/10.1086/266350
• Hu, L. T., & Bentler, P. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling: A Multidisciplinary Journal, 6(1), 1–55. https://doi.org/10.1080/10705519909540118
• Keller, K. L. (1993). Conceptualizing, measuring, and managing customer-based brand equity. Journal of Marketing, 57(1), 1–22. https://doi.org/10.1177/002224299305700101
• Kirmani, A., & Rao, A. R. (2000). No pain, no gain: A critical review of the literature on signaling unobservable product quality. Journal of Marketing, 64(2), 66–79. https://doi.org/10.1509/jmkg.64.2.66.18000
• McCroskey, J. C., & Jenson, T. A. (1975). Image of mass media news sources. Journal of Broadcasting, 19(2), 169–180. https://doi.org/10.1080/08838157509363777
• Newell, S. J., & Goldsmith, R. E. (2001). The development of a scale to measure perceived corporate credibility. Journal of Business Research, 52(3), 235–247. https://doi.org/10.1016/S0148-2963(99)00104-6
• Petty, R. E., & Cacioppo, J. T. (1986). The elaboration likelihood model of persuasion. Advances in Experimental Social Psychology, 19, 123–205. https://doi.org/10.1016/S0065-2601(08)60214-2
• Spence, M. (1973). Job market signaling. Quarterly Journal of Economics, 87(3), 355–374. https://doi.org/10.2307/1882010

13. Items of the Scale