Opinion leadership and data quality in consumer decision-making: a phase-specific analysis of the rational decision process

Purpose In the digital marketplace, consumers increasingly rely on opinion leaders to guide purchase decisions, yet the quality of information these influencers provide varies considerably. This study integrates opinion leadership theory with data quality research to examine how both source characteristics and information quality influence the five phases of rational consumer decision-making for high-value purchases. Design/methodology/approach Drawing on the Elaboration Likelihood Model, Uncertainty Reduction Theory, Social Proof Theory, and Information Processing Theory, we develop an integrated model hypothesizing phase-specific effects of opinion leadership and data quality. Empirical data were collected from 534 respondents via an online survey using a prototypical automotive opinion leader as stimulus. Data were analyzed using PLS-SEM with bootstrapping (5,000 subsamples). Findings Opinion leaders positively influence all five decision phases (need recognition, information search, evaluation of alternatives, selection and purchase, post-purchase evaluation), with effects strengthening across phases (ß = 0.373 to 0.717). Data quality influences the first four phases but not post-purchase evaluation (ß = 0.123, p = 0.205). Critically, data quality moderates opinion leadership effects only during the pre-purchase phases (DM1-3), not during purchase or post-purchase. These phase-specific patterns align with theoretical predictions about uncertainty reduction and cognitive load. Originality/value This study makes three novel contributions: (1) theoretical integration of opinion leadership and data quality within established consumer behavior frameworks, (2) phase-specific analysis revealing when each factor matters most, and (3) identification of boundary conditions where data quality ceases to moderate social influence. Results inform influencer marketing strategy, platform design for information quality, and consumer protection policies.