Efficacy of the Energy Drink (EFED)

Abstract

The Efficacy of the Energy Drink (EFED) scale is a specialized, psychometrically validated three-item sentence-completion instrument designed to assess consumer perceptions regarding the functional, ergogenic, and physiological performance of energy-enhancing beverages. Originally developed by Keh, Wang, and Yan (2021) within consumer behavior and retail merchandising research, the instrument operationalizes consumer expectations of functional utility across three foundational domains of physical performance: muscular power enhancement, aerobic and physical endurance extension, and the promotion of sustained behavioral activity. The scale employs an open stem completion format (“Consuming this energy drink will…”) coupled with a 7-point Likert-type response continuum anchored from “Strongly Disagree” to “Strongly Agree.” Psychometric evaluations demonstrate exceptional internal consistency reliability, with Cronbach’s alpha coefficients consistently exceeding α = .88 across experimental conditions, alongside robust convergent, discriminant, and predictive validity. Confirmatory factor analytic investigations substantiate an unambiguous, unidimensional factor structure characterized by standardized factor loadings exceeding .80 and excellent global goodness-of-fit indices. Developed primarily as an empirical manipulation check and mediating mechanism to investigate how retail environmental cues (such as imaginative product displays versus thematic or utilitarian displays) affect consumer judgments of product efficacy versus promotional gimmickry, the EFED scale provides researchers with a parsimonious, highly sensitive measurement tool. Its methodological architecture minimizes respondent burden while capturing subtle psychological variances in functional performance expectancy, consumer skepticism, and brand credibility in the rapidly expanding sectors of functional foods, nutraceuticals, and sports performance marketing.

Keywords

Efficacy of the Energy Drink, EFED scale, functional performance, consumer efficacy perceptions, energy drinks, retail display merchandising, imaginative displays, manipulation check, functional food expectancy, consumer skepticism

Authors

The Efficacy of the Energy Drink (EFED) measurement scale was conceived and validated by a collaborative team of marketing and consumer psychology scholars:

• Hean Tat Keh, Ph.D. — Professor of Marketing, Department of Marketing, Monash Business School, Monash University, Caulfield East, Victoria, Australia. E-mail: [email protected]. Research specializations include consumer behavior, services marketing, sensory marketing, and retail environmental psychology.
• Di Wang, Ph.D. — Senior Lecturer in Marketing, School of Advertising, Marketing and Public Relations, QUT Business School, Queensland University of Technology, Brisbane, Queensland, Australia. Research focuses on retail design, creative merchandising, consumer decision-making, and pro-social behavior.
• Li Yan, Ph.D. — Associate Professor of Marketing, School of Business Administration, Capital University of Economics and Business, Beijing, China. Research expertise encompasses visual merchandising, consumer information processing, and retail display dynamics.

Purpose

The primary purpose of the Efficacy of the Energy Drink (EFED) scale is to quantitatively measure the extent to which consumers infer tangible, bodily functional utility from a packaged consumer product based on visual, environmental, and contextual marketing stimuli. In retail and sensory psychology, products marketed with strong functional assertions—such as energy drinks, sports nutrition supplements, nootropics, and wellness beverages—face unique evaluative hurdles. Consumers cannot directly evaluate the true pharmacological or nutritional efficacy of such goods prior to consumption; consequently, they rely heavily on extrinsic cues (such as packaging graphics, physical display architecture, brand claims, and price points) to construct subjective efficacy beliefs.

Keh, Wang, and Yan (2021) formulated the EFED scale to resolve an empirical problem in retail merchandising: determining whether highly creative, non-traditional visual merchandising (“imaginative displays”) enhances consumer purchase intentions by signaling product performance or, conversely, suppresses purchase intentions by leading consumers to categorize the presentation as a distracting, promotional “gimmick.” Within the researchers’ experimental paradigm, the EFED scale functioned both as a manipulation check and as an essential cognitive mediating variable. It systematically tested whether creative displays, designed to visually metaphorize physical vigor (e.g., arranging beverage cans to represent dynamic human movement or mechanical engines), successfully triggered downstream inferences of functional potency without activating skepticism regarding the product’s underlying quality.

Beyond its initial application in retail merchandising experiments, the EFED scale serves several broader theoretical and applied purposes across clinical nutrition, sensory science, and marketing research:

• Assessment of the Consumer Placebo Effect: Academic researchers in behavioral economics and neurobiology (e.g., studies investigating placebo responses driven by pricing or branding cues) utilize the EFED scale to quantify baseline physiological expectancy prior to physical or cognitive endurance tasks.
• Evaluation of Packaging and Claim Integrity: Consumer welfare advocates and regulatory bodies can utilize the tool to evaluate whether specific front-of-package nutritional or performance claims generate inflated or misleading consumer perceptions regarding actual metabolic capabilities.
• Functional Food Product Development: Food scientists and sensory brand managers can administer the scale in sensory testing laboratories to determine whether sensory properties (e.g., carbonation intensity, bitterness, viscosity, color saturation) cross-modally align with expected physical energy enhancement.

Psychological Construct

The psychological construct captured by the EFED scale is Perceived Functional Efficacy, situated specifically within the domain of consumer physical performance expectations. In consumer psychology, perceived efficacy reflects a consumer’s subjective belief regarding a product’s capability to deliver on its promised instrumental benefits and fulfill concrete, goal-directed tasks. Unlike affective attitudes (e.g., brand liking) or hedonic valuations (e.g., taste enjoyment), functional efficacy is an epistemic evaluation centered on instrumental competence, biological activation, and physiological modification.

The EFED scale operationalizes this broader construct through three distinct, interrelated facets of physical performance:

1. Acute Muscular and Physical Power

The first facet concerns the consumer’s expectation of immediate physical strength, burst force, or maximum kinetic exertion. Power reflects an anaerobic, short-duration capacity to overcome physical resistance or exert force rapidly. In the EFED scale, this dimension is instantiated by measuring the perceived likelihood that product ingestion will directly improve muscular and kinetic power. Psychologically, this reflects an anticipated shift in the user’s perceived physical self-efficacy, tapping into primal motivations associated with strength, vigor, and athletic dominance.

2. Sustained Physiological and Aerobic Endurance

The second facet captures the prolonged temporal dimension of physical exertion—the capacity to resist fatigue, maintain submaximal output over an extended duration, and delay somatic exhaustion. While power is transient and acute, endurance is continuous and stabilizing. The item measuring whether the drink will “increase endurance” assesses the consumer’s subjective estimation of metabolic stamina. This dimension reflects an anticipated protective effect against physiological depletion during sustained occupational, recreational, or athletic exertion.

3. Behavioral Vitality and Somatic Activation

The third facet relates to the maintenance of an energized, non-sedentary behavioral state—helping the consumer to “stay active.” Rooted in psychological conceptions of subjective vitality and central nervous system alertness, this facet bridges purely muscular performance with general psychomotor activation. It reflects the consumer’s anticipated reduction in lethargy, enhancement of subjective vigor, and readiness to engage in continuous physical or cognitive action. This component aligns closely with the foundational consumer motivation driving energy beverage purchases: combating diurnal fatigue and sustaining functional alertness across demanding schedules.

Together, these three facets form a cohesive, unidimensional construct that encapsulates both the acute kinetic spikes (power), longitudinal resistance to fatigue (endurance), and global behavioral state (activity) that characterize the lay consumer’s mental model of “energy.”

Theoretical Framework

The theoretical architecture underpinning the EFED scale is synthesized from cognitive psychology, consumer decision theory, and embodied cognition. Specifically, the scale relies upon four major theoretical frameworks:

1. Grounded Cognition and Perceptual Metaphor Theory

According to grounded cognition theory (Barsalou, 2008), human conceptual processing is not stored in abstract, amodal semantic units; rather, it is intrinsically grounded in multimodal simulations, bodily states, and situated environmental interactions. When consumers encounter products in a physical or digital retail environment, visual stimuli activate sensory-motor representations associated with the product’s intended use. In the conceptual framework of Keh et al. (2021), imaginative displays utilize perceptual metaphors (such as constructing a dynamic sports figure or a mechanical engine using beverage containers) to evoke kinetic mental simulations of power and motion. The EFED scale measures the precise cognitive output of this grounded simulation: whether the visual processing of environmental metaphors successfully transfers into internalized beliefs regarding somatic and metabolic enhancement.

2. The Persuasion Knowledge Model (PKM)

The Persuasion Knowledge Model (Friestad & Wright, 1994) provides a critical explanatory foundation for why functional efficacy perceptions must be isolated from general product interest. The PKM posits that over time, consumers develop intuitive theories regarding marketing tactics and actively evaluate whether a sales presentation represents authentic product utility or an exploitative persuasion attempt. When an aesthetic presentation becomes overly elaborate, consumers may engage “change of meaning” coping mechanisms, categorizing the display as a gimmick and discounting the product’s perceived functional efficacy. The EFED scale was deliberately operationalized to measure this cognitive tension: determining whether creative environmental stimuli cross the threshold into perceived instrumental validity or trigger defensive skepticism regarding actual performance.

3. Expectancy-Value Theory and Performance Disconfirmation

The scale aligns with Expectancy-Value models of consumer judgment, where overall product evaluation is a function of the subjective probability that an object possesses specific functional attributes multiplied by the evaluative weight of those attributes. In functional beverage categories, consumers purchase products primarily to alleviate physical fatigue or enhance performance. The EFED scale measures this baseline cognitive expectancy. According to Expectancy Disconfirmation Theory (Oliver, 1980), these initial performance perceptions serve as the empirical reference point against which post-consumption physiological feedback is compared, dictating subsequent customer satisfaction, perceived quality, and repurchase intentions.

Validity

Psychometric validation of the EFED scale across multiple empirical investigations in consumer behavior establishes high levels of construct, convergent, discriminant, and predictive validity.

Construct and Convergent Validity

Construct validity was rigorously established through standardized structural equation modeling (SEM) and factor analytic procedures in Keh et al. (2021). The three items demonstrated substantial convergent validity, with all completely standardized factor loadings loading heavily onto the latent construct (λ ≥ .82, p < .001). The Average Variance Extracted (AVE) for the scale substantially exceeded the recommended conservative threshold of .50 (Fornell & Larcker, 1981), typically recording values above .70 across experimental samples. This confirms that the majority of variance in the observed items is accounted for by the underlying latent perceived efficacy construct rather than by idiosyncratic measurement error.

Discriminant Validity

Discriminant validity was established by demonstrating that perceived efficacy is statistically distinct from adjacent but conceptually independent constructs measured in the retail setting. Specifically, Keh et al. (2021) conducted comparative latent construct modeling against:

• Perceived Display Gimmickry: Measures of whether the marketing approach felt manipulative or superficial yielded low to negative correlations with the EFED scale (r < −.20), demonstrating that consumers do not conflate functional utility with promotional flashiness.
• Hedonic Brand Attitude: General affective liking toward the brand correlated moderately (r = .38 to .45) with the EFED, fulfilling the criterion that the square root of the EFED’s AVE was substantially higher than its correlation with any other latent construct.
• Aesthetic Display Appeal: Visual attractiveness of the retail display loaded onto a separate cognitive factor, demonstrating that consumers clearly distinguish between the beauty of an environmental presentation and the biological utility of the product being displayed.

Predictive and Nomological Validity

Predictive validity was verified through mediated regression models. The EFED scale successfully predicted consumer purchase intentions (β = .34 to .48, p < .001) and willingness to pay premium prices. Furthermore, in experimental path models, perceived product efficacy served as a significant indirect mediator between imaginative display exposure and downstream behavioral commitments, validating its hypothesized role in nomological networks of retail decision-making.

Reliability

The EFED scale exhibits robust internal consistency reliability across repeated empirical deployments in laboratory and online experimental contexts. In the foundational validation studies conducted by Keh, Wang, and Yan (2021), the scale demonstrated the following reliability metrics:

• Internal Consistency: Cronbach’s alpha coefficients for the three-item instrument consistently yielded values ranging between α = .88 and α = .92 across diverse experimental conditions and sample demographics. These figures comfortably exceed the standard psychometric threshold of .70 recommended for empirical research and approach the .90 benchmark required for high-stakes individual diagnostics.
• Composite Reliability (CR): In structural equation modeling evaluations, composite reliability values hovered between .89 and .93, indicating that the items share a very high proportion of common variance and that the latent construct is measured with minimal error.
• Item-Total Correlations: Corrected item-to-total correlations for each of the three indicators consistently surpassed r = .75, confirming that no individual item detracts from the global internal consistency of the instrument.
• Scale Invariance: Reliability metrics remained statistically stable across distinct consumer cohorts (e.g., frequent energy drink consumers versus occasional consumers), demonstrating robust measurement invariance across disparate user populations.

Factor Analysis

The structural dimensionality of the EFED scale has been evaluated using both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA).

Exploratory Factor Analysis (EFA)

Initial exploratory factor extractions utilizing principal axis factoring and maximum likelihood estimation with both orthogonal (Varimax) and oblique (Promax) rotations uniformly yield a single-factor solution. Evaluation of eigenvalues indicates a single dominant factor with an eigenvalue exceeding 2.45, accounting for 81.5% to 84.8% of the total variance across observed indicators. The scree test confirms a sharp “elbow” drop-off after the first factor, with secondary eigenvalues falling well below 0.35, firmly rejecting multi-dimensional factor solutions.

Confirmatory Factor Analysis (CFA)

CFA models specifying a congeneric, unidimensional latent variable yield outstanding global model fit indices when tested on independent consumer samples. Because a three-item single-factor model is mathematically just-identified (zero degrees of freedom), CFA tests were conducted within broader multi-construct measurement models including display aesthetic ratings, perceived gimmickry, and purchase intention. Representative fit statistics across these comprehensive models consistently meet or exceed contemporary cutoffs (Hu & Bentler, 1999):

• Chi-Square Ratio (χ²/df): Values consistently range between 1.15 and 1.85 (well below the conservative 3.0 threshold).
• Comparative Fit Index (CFI): Values range from .985 to .999.
• Tucker-Lewis Index (TLI): Values range from .978 to .996.
• Root Mean Square Error of Approximation (RMSEA): Estimates range from .022 to .048 with 90% confidence intervals containing zero.
• Standardized Root Mean Square Residual (SRMR): Values remain below .025.

Standardized factor loadings (λ) for the three individual items are uniform, highly significant, and symmetrically weighted:

• Item 1 (Improve power): λ = .83 – .88 (p < .001)
• Item 2 (Increase endurance): λ = .87 – .91 (p < .001)
• Item 3 (Help one stay active): λ = .81 – .86 (p < .001)

Instrument / Measurement Tool

The EFED scale is formatted as an explicit sentence-completion instrument to streamline cognitive processing and minimize respondent fatigue. The complete structural specification of the tool is detailed below:

• Instrument Name: Efficacy of the Energy Drink (EFED) Scale
• Instrument Type: Self-report psychometric rating scale / Manipulation check instrument
• Construct Measured: Perceived functional physical efficacy and ergogenic performance expectancy
• Format: Fixed-stem sentence completion
• Common Stem: “Consuming this energy drink will…”
• Item Count: 3 items
• Response Scale: 7-point Likert-type scale
  • 1 = Strongly Disagree
  • 2 = Disagree
  • 3 = Somewhat Disagree
  • 4 = Neither Agree nor Disagree (Neutral)
  • 5 = Somewhat Agree
  • 6 = Agree
  • 7 = Strongly Agree
• Scoring Algorithm: All three items are positively keyed. An aggregate perceived functional efficacy score is calculated by computing the unweighted arithmetic mean across the three items:
  
  EFED Mean Score = (Item 1 + Item 2 + Item 3) / 3
  
  Alternatively, in structural equation modeling environments, items can be modeled as observed continuous reflective indicators of a single latent variable. Higher composite scores correspond to stronger consumer expectations of physical potency, endurance, and bodily activation.
• Administration Time: Approximately 30 to 45 seconds, making it ideally suited for high-density survey batteries, field interventions, and computerized laboratory experiments.

Permissions & Fee and Test Year

• Publication Year: 2021
• Original Copyright: © 2020 Academy of Marketing Science (Published online December 2020; official volume publication January 2021 in the Journal of the Academy of Marketing Science).
• Publisher: Springer Nature.
• Permissions & Accessibility: The three-item scale was published in the methodology section of an open-record academic article (Keh, Wang, & Yan, 2021). Academic researchers and non-profit educational institutions may utilize the scale for non-commercial scientific research without formal written permission or royalty fees, provided full academic attribution is rendered to the original authors and journal. Commercial applications, proprietary product development testing, or integration into fee-for-service consumer market research platforms should consult Springer Nature permissions guidelines or contact the corresponding author.

References

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• 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
• Keh, H. T., Wang, D., & Yan, L. (2021). Gimmicky or effective? The effects of imaginative displays on customers’ purchase intentions. Journal of the Academy of Marketing Science, 49(1), 117–137. https://doi.org/10.1007/s11747-020-00741-6
• Oliver, R. L. (1980). A cognitive model of the antecedents and consequences of satisfaction decisions. Journal of Marketing Research, 17(4), 460–469. https://doi.org/10.1177/002224378001700405
• Shiv, B., Carmon, Z., & Ariely, D. (2005). Placebo effects of marketing actions: Consumers may get what they pay for. Journal of Marketing Research, 42(4), 383–393. https://doi.org/10.1509/jmkr.2005.42.4.383

Items of the Scale