Green Claim Specificity in Sustainability Advertising: A Systematic Review and Future Research Agenda

Abstract

Purpose - The increasing use of environmental claims in advertising has intensified concerns regarding their credibility, verifiability and potential to mislead consumers. This study systematically reviews how green claim specificity influences consumer responses to sustainability advertising, with particular emphasis on claim credibility, advertising skepticism, green trust, ecological brand image and purchase-related outcomes. It further examines why specific environmental claims generally perform better than vague claims, why greater specificity may sometimes produce adverse responses, and how verification cues, message execution, corporate environmental performance and consumer knowledge condition these effects. Design/methodology/approach - A systematic literature review was conducted using a SPAR-4-SLR-guided search and screening process. Searches across Scopus, Web of Science and scholarly publisher databases were supplemented by backward and forward citation chaining. Following the application of predefined inclusion and exclusion criteria, 60 peerreviewed journal articles published between 1993 and 2026 were retained for analysis. The selected studies were coded and synthesized through the TCCM framework to evaluate their theoretical foundations, attributes and methodological approaches. Findings - The findings indicate that specificity is not inherently persuasive; rather, its effectiveness depends on whether the claim is perceived as diagnostic, verifiable and consistent with the advertiser’s actual environmental performance. Specific claims generally strengthen credibility, green trust and ecological brand image, which subsequently improve brand evaluations and purchase intentions. Conversely, perceived manipulation, greenwashing, consumer confusion and skepticism weaken or reverse these effects. Specificity may also backfire when supporting evidence is inaccessible, technical detail creates cognitive overload, the claim exceeds the firm’s perceived competence, or environmental messaging conflicts with corporate conduct. Recent research extends the field by identifying curiosity, emotional ambivalence, disclosure and boycott intention as relevant mechanisms. Originality/value - The study integrates claim formulation, verification cues and consumer motive attribution within a Specificity–Credibility– Skepticism Contingency Model. It distinguishes numerical, process, temporal, comparative, source and boundary specificity; reconnects specificity with substantive and posturing claims, cognitive load, country disposition and executional greenwashing; and proposes a research agenda for factorial experiments, field studies, longitudinal designs and crosscountry analysis.