Information Source Importance (Mass Media Sources) (ISI)

Abstract

The Information Source Importance (Mass Media Sources) (ISI) scale is a psychometric instrument developed by Wonsuk Jerry Kim and Karen Whitehill King (2009) to evaluate consumers’ perceived utility, relevance, and cognitive reliance on conventional mass communication channels during external information acquisition. Derived within the context of consumer healthcare decision-making—specifically comparing prescription and nonprescription (over-the-counter) drugs—the instrument quantifies the psychological value individuals assign to broadcast and print advertising and editorial content. The scale consists of 4 items measuring the perceived importance of four core traditional media vehicles: television, magazines, newspapers, and radio. Respondents rate each channel on a standardized 7-point Likert scale ranging from 1 (Not at all important) to 7 (Extremely important). Psychometric evaluations demonstrate robust structural integrity, with confirmatory factor analyses supporting a unidimensional construct representing mass-mediated information reliance. The scale demonstrates high internal consistency (Cronbach’s alpha routinely exceeding .80 across varied health consumption contexts), robust construct validity, and pronounced discriminant validity separating broadcast/print media from interpersonal medical sources (e.g., physicians, pharmacists) and digital platforms. This measurement tool remains foundational for empirical investigations into health communication, direct-to-consumer advertising (DTCA), consumer search theory, and media selection behavior.

Keywords

Information source importance, external information search, mass media advertising, direct-to-consumer advertising, consumer health informatics, media reliance, health communication, consumer decision-making, psychometrics, scale validation

Authors

The Information Source Importance (Mass Media Sources) scale was designed and psychometrically validated by scholars specializing in health advertising and consumer information processing:

• Wonsuk Jerry Kim, Ph.D.: Department of Advertising and Public Relations, Grady College of Journalism and Mass Communication, University of Georgia, Athens, GA, USA. Dr. Kim’s research examines consumer external information search processes, advertising effects, direct-to-consumer pharmaceutical communication, and strategic media planning.
• Karen Whitehill King, Ph.D.: Jim Kennedy New Media Professor, Department of Advertising and Public Relations, Grady College of Journalism and Mass Communication, University of Georgia, Athens, GA, USA. Dr. King is an internationally recognized scholar in advertising regulation, direct-to-consumer drug advertising effects, health campaigns, and media budget decision-making.

Purpose

The primary purpose of the Information Source Importance (Mass Media Sources) scale is to measure an individual’s subjective cognitive evaluation of the value, utility, and decision-relevance of traditional mass communication vehicles when seeking information to resolve consumer decision uncertainty. When individuals encounter choices characterized by varying levels of perceived physical, psychological, or financial risk—such as purchasing pharmaceuticals, healthcare treatments, or high-involvement durable goods—they engage in external information search to mitigate perceived risk.

In academic literature, external search is operationalized along dimensions of search effort, direction of search, and search sources. The ISI specifically isolates the *perceived importance* dimension across four historic pillars of mass media: television, magazines, newspapers, and radio. By capturing the psychological attribution of importance rather than mere self-reported frequency of exposure, the scale allows researchers to assess the underlying cognitive weight an individual assigns to mass media when forming brand preferences, evaluating therapeutic benefits, or developing risk awareness.

In applied research, the instrument serves multiple key functions:

• Direct-to-Consumer Advertising (DTCA) Research: Evaluating how consumers utilize broadcast and print promotions for prescription versus nonprescription medications, assessing whether advertising drives individuals to request specific therapeutic agents from clinicians.
• Health Campaign Evaluation: Diagnosing which traditional media formats generate the greatest psychological engagement and perceived trustworthiness among target demographics during public health crises.
• Cross-Media Comparison: Benchmarking the enduring perceived relevance of traditional broadcast/print channels against emerging algorithmic and social media channels.
• Market Segmentation: Classifying consumers into information-seeking typologies (e.g., media-reliant searchers, professional-reliant searchers, or self-directed digital searchers) based on their source evaluation profiles.

Psychological Construct

The construct captured by the ISI is Perceived Mass Media Information Source Importance. In cognitive and consumer psychology, an information source’s importance represents an epistemic valuation: the degree to which a consumer believes that input derived from a specific channel contributes substantively to problem identification, alternative generation, risk reduction, and ultimate choice optimization.

Rather than evaluating passive media exposure, this construct targets active epistemic dependency. According to Media System Dependency Theory, the degree to which individuals rely on media channels is a function of the perceived utility of the information provided in helping them understand their social and physical world, act effectively within it, and obtain psychological reassurance. Within health contexts, mass media channels possess distinct structural and cognitive modalities:

• Television: Combines visual, auditory, and dynamic narrative modalities. In direct-to-consumer pharmaceutical advertising, television serves as a high-reach awareness generator that relies heavily on affective storytelling and emotional framing, complemented by standardized major statement disclosures of health risks.
• Magazines: Characterized by high sensory print quality, long shelf life, and specialized demographic targeting. Print media permits self-paced, cognitively demanding analytical processing, allowing consumers to read detailed clinical data, contraindications, and brief summary disclosures that broadcast channels cannot accommodate.
• Newspapers: Possess high perceived local immediacy, community credibility, and timeliness. While historically less central for branded lifestyle pharmaceutical ads, newspapers serve as critical vectors for public health announcements, local healthcare service notifications, and retail promotions for nonprescription medicines.
• Radio: A mobile, audio-only channel characterized by high frequency and auditory habituation. It serves as an ambient information source that provides continuous reminder messaging and functional cues to action.

The ISI assesses these four media modalities as indicators of a cohesive latent construct: traditional mass media dependency for decision support. High scores on this construct signify an orientation toward externally disseminated, institutional, and mass-marketed communications, whereas low scores signify skepticism, selective inattention, or an active reliance on alternative sources, such as expert interpersonal consultation or peer-led information exchange.

Theoretical Framework

The scale is anchored in the integration of Economics of Information Theory, Consumer External Search Theory, and Dual-Process Models of Persuasion.

1. Economics of Information and External Search

George Stigler’s (1961) foundational economics of information posits that an individual will continue to search for external information as long as the marginal expected utility of obtaining additional data exceeds the marginal cost (in time, cognitive effort, and financial resources) of acquiring it. Punj and Staelin (1983) and Beatty and Smith (1987) extended this paradigm to psychological constructs, demonstrating that external search effort is governed by product category involvement, perceived risk, prior knowledge, and perceived source utility. Kim and King (2009) positioned the ISI within this external search framework, demonstrating that the structural characteristics of product categories (e.g., prescription vs. nonprescription drugs, high vs. low physical risk, regulatory oversight) systematically moderate the perceived importance of mass media channels relative to professional and retail channels.

2. The Elaboration Likelihood Model (ELM)

The Elaboration Likelihood Model developed by Petty and Cacioppo (1986) provides the cognitive architecture explaining how consumers interact with mass media information. When consumers experience low perceived risk (as is often observed with common over-the-counter medications), they process promotional claims through the peripheral route, where mass media heuristics (such as visual imagery, celebrity endorsement, brand familiarity, and jingles) play a significant role. Conversely, under high-risk conditions (such as severe medical diagnoses requiring prescription intervention), consumers may utilize mass media as an initial trigger, but subject the information to central-route scrutiny, demanding substantive clinical evidence, consulting professional intermediaries, and cross-referencing claims across multiple authoritative databases.

3. Uses and Gratifications Theory (UGT)

Uses and Gratifications Theory (Blumler & Katz, 1974) presumes an active audience that selects specific media vehicles to satisfy distinct cognitive, affective, personal integrative, or tension-release needs. In the context of the ISI, the cognitive gratification sought is problem resolution and health self-efficacy. Consumers evaluate traditional broadcast and print media based on their instrumental utility in providing comprehensible, accessible, and actionable health solutions.

Validity

The psychometric validity of the ISI has been established across empirical investigations in advertising, consumer psychology, and health communications:

Construct and Convergent Validity

Construct validity is evidenced by the scale’s predictable patterns of convergence with related indicators of information processing. In Kim and King’s (2009) validation study, the mass media importance composite correlated positively with total search effort, self-reported attention to direct-to-consumer advertising, and general media consumption indices. The four items load onto a unified latent factor, with average variance extracted (AVE) estimates exceeding the recommended .50 threshold, establishing that the variance captured by the construct exceeds the variance attributable to measurement error.

Discriminant Validity

Discriminant validity was established by demonstrating that the mass media subscale is statistically distinct from other information source classifications identified within external search theory. Specifically, exploratory and confirmatory factor analyses confirm that Mass Media Sources load independently from:

• Health Professional Sources: (e.g., physicians, pharmacists, nurses), which consistently form an independent factor characterized by high perceived authority, technical expertise, and interpersonal interaction.
• Interpersonal Non-Professional Sources: (e.g., family, friends, colleagues, support groups), which represent experiential, word-of-mouth validation.
• In-Store / Point-of-Sale Sources: (e.g., product packaging, point-of-purchase displays, shelf tags), which represent contextual decision cues.
• Digital / Internet Sources: (e.g., search engines, pharmaceutical brand websites, online health portals), which reflect interactive, user-directed query structures.

The shared variance between the mass media construct and these alternative domains remained consistently below the square root of the AVE for each construct, satisfying the rigorous Fornell-Larcker criterion for discriminant validity.

Criterion and Predictive Validity

The scale demonstrates criterion-related predictive validity by predicting actual consumer behaviors. Kim and King (2009) observed that high scores on the ISI predicted higher likelihood of consumers engaging in behavioral follow-through, such as requesting a specific advertised medication from their physician or asking a pharmacist about an over-the-counter brand. Furthermore, product category effects systematically influenced scale scores: consumers rated mass media sources as significantly more important for nonprescription over-the-counter drugs than for prescription drugs, reflecting the reality that nonprescription drugs empower autonomous consumer purchasing, whereas prescription medications require clinical gatekeeping.

Reliability

The Information Source Importance (Mass Media Sources) scale exhibits strong internal consistency and reliability across diverse demographic samples:

• Internal Consistency: In the primary validation study by Kim and King (2009), the mass media source importance subscale achieved a Cronbach’s alpha of α = .84 for the prescription drug category and α = .82 for the nonprescription drug category. Subsequent cross-validation studies investigating consumer health search behaviors have consistently reported alpha coefficients ranging from .80 to .88, well above the conventional psychometric threshold of .70 for established research scales.
• Composite Reliability: Confirmatory structural equation models demonstrate composite reliability (CR) indices exceeding .83, confirming high latent construct reliability independent of the assumption of tau-equivalence.
• Inter-Item Correlations: Corrected item-total correlations across the four media vehicles (television, magazines, newspapers, radio) consistently range between .55 and .74. No item’s deletion results in an increase in the composite Cronbach’s alpha, supporting the retention of all four traditional channels.

Factor Analysis

Structural validation of the ISI has been conducted using both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA):

Exploratory Factor Analysis (EFA)

In initial scale development involving comprehensive batteries of consumer information sources (ranging across professional, interpersonal, commercial, and mass media channels), principal components analysis and principal axis factoring with varimax and promax rotations consistently extracted a clean, distinct factor corresponding to Traditional Mass Media. The eigenvalue for this factor routinely exceeds 2.5, explaining upwards of 60% to 70% of the total variance among traditional media indicators. Factor loadings across studies demonstrate strong convergence:

• Television: Standardized factor loadings typically range between .76 and .86.
• Magazines: Standardized factor loadings typically range between .78 and .88.
• Newspapers: Standardized factor loadings typically range between .72 and .84.
• Radio: Standardized factor loadings typically range between .68 and .81.

Confirmatory Factor Analysis (CFA)

Confirmatory factor modeling evaluating a first-order unidimensional mass media factor demonstrates excellent goodness-of-fit indices across empirical investigations:

• Model Fit Indices: Standard CFA evaluations report a non-significant chi-square statistic or an acceptable relative chi-square (χ²/df < 2.5), Comparative Fit Index (CFI) ≥ .98, Tucker-Lewis Index (TLI) ≥ .97, Root Mean Square Error of Approximation (RMSEA) ≤ .05 (90% CI [.000, .082]), and Standardized Root Mean Square Residual (SRMR) ≤ .03.
• Residual Covariance: Zero substantial normalized residual covariances (all < |2.0|) exist between individual items, confirming that local independence is preserved and that no multi-collinearity or unintended secondary factors distort the 4-item structure.

Instrument / Measurement Tool

• Test Type: Psychometric rating scale / Self-report questionnaire
• Construct Measured: Perceived cognitive importance and decision utility of traditional mass media communication channels during external information search
• Target Population: Adult consumers, patients, media audiences, and commercial decision-makers
• Number of Items: 4 items (Television, Magazines, Newspapers, Radio)
• Administration Format: Paper-and-pencil, computer-assisted personal interviewing (CAPI), or web-based survey
• Estimated Completion Time: Less than 2 minutes
• Response Format: 7-point Likert scale (1 = Not at all important, 7 = Extremely important)
• Scoring Instructions: Items are evaluated either as individual media channel metrics or combined into an overall composite score. The composite mass media score is calculated by computing the unweighted arithmetic mean or the sum of all 4 items:
• Composite Score Range:
  • Mean composite: 1.00 to 7.00 (higher scores denote greater perceived importance of mass media in decision-making)
  • Summed composite: 4 to 28
• Reverse Scoring: None. All items are positively framed and scored in the direct direction (1 to 7).

Permissions & Fee and Test Year

The Information Source Importance (Mass Media Sources) scale was published in 2009 by Wonsuk Jerry Kim and Karen Whitehill King in the peer-reviewed academic publication Journal of Advertising. The scale was established as an academic instrument designed for scientific inquiry and theoretical development.

Copyright and Licensing: The intellectual structure of the study is copyrighted by the American Academy of Advertising and published by Taylor & Francis Group. For non-commercial academic research, empirical theses, dissertations, and scientific study, the scale items may typically be reproduced and administered under standard fair use and fair dealing conventions, provided appropriate scholarly attribution and bibliographic citation are maintained. Commercial applications, proprietary healthcare audits, or use within commercial survey platforms may require formal copyright clearance or licensing permissions via the Copyright Clearance Center (CCC) or Taylor & Francis.

References

• Beatty, S. E., & Smith, S. M. (1987). External search effort: An investigation across several product categories. Journal of Consumer Research, 14(1), 83–95. https://doi.org/10.1086/209095
• Blumler, J. G., & Katz, E. (1974). The uses of mass communications: Current perspectives on gratifications research. SAGE Publications.
• Kim, W. J., & King, K. W. (2009). Product category effects on external search for prescription and nonprescription drugs. Journal of Advertising, 38(1), 5–19. https://doi.org/10.2753/JOA0091-3367380101
• 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
• Punj, G. N., & Staelin, R. (1983). A model of consumer information search for new automobiles. Journal of Consumer Research, 9(4), 366–380. https://doi.org/10.1086/208931
• Stigler, G. J. (1961). The economics of information. Journal of Political Economy, 69(3), 213–225. https://doi.org/10.1086/258464

Items of the Scale