We study information transmission in a model of career concerns in which experts evaluate their worth based on social comparisons. There are two experts, each of whom receives an informative signal about the state of the world and makes a statement to the principal. The quality of the signal each expert receives is unknown to the other players, and the experts differ in the prior that their signal is fully informative. Accordingly, we speak of the stronger and the weaker expert, where the stronger expert is ex-ante more likely to receive a better signal. We show that expert heterogeneity and social comparisons drive expert dissent. We identify an incentive for the stronger expert to deliberately misreport an informative signal in order to sabotage the weaker expert, garble the principal’s evaluation, and maintain her initial advantage. In equilibrium, this expert may even completely contradict her signal and the decision of the other expert. This result suggests a new rationale for social dissent that may help shed light on current polarization trends.