Identifying fake experts: a conceptual framework and case study of illegitimate expertise in climate change and COVID-19 misinformation and its implications for communication theory

Abstract The concept of the “fake expert” has been used as a label to delegitimize established expertise but also refers to experts that are invoked to support misinformation claims. This study examines how “fake experts” and their expertise are constructed in misinformation. Analyzing fact-checked misinformation on climate change and COVID-19, we investigate how sources are framed as experts (RQ1), how their expertise is linked to misinformation (RQ2), and to what extent these references are misleading or inaccurate (RQ3). Our findings show that expertise in misinformation is shaped more by content and communicative context than by credentials alone. Misinformation employs rhetorical strategies such as selective quoting and epistemic trespassing to create credibility. We propose a framework for identifying “illegitimate” expertise in misinformation, integrating content- and actor-based indicators. This framework offers a structured approach for analyzing how misinformation manipulates expert credibility and provides a foundation for future empirical research.