In This House We Believe in … Empirical Evidence? Power and Knowledge Dynamics in Congressional Hearings

This study examines the use of empirical discourse in US House of Representatives committee hearings (1997–2016, N = 12, 428), analyzing over 5.8 million sentences using machine learning classification. We find that empirical discourse has increased over time, not necessarily as a marker of evidence‐based policymaking, but driven mainly by the minority. Minority legislators—both Republican and Democrat—rely on empirical arguments more than majority legislators, and more so as the majority‐minority control gap increases. Senior minority members use substantially more empirical discourse, suggesting that empirical discourse is acquired as a substitute for power. We estimate the effect as ranging between 15% and 40%, depending on seniority. Using an event study design, we find that when power shifts (twice throughout the duration of our study), those who used less empirical discourse subsequently use more of it, and vice versa; this is also true at the individual level for House members who survived reelection but switched from being in the minority to being in the majority or vice versa. Overall, these findings support a “Power or Knowledge” framework, whereby the majority controls the agenda whereas the minority leverages empirical discourse to assert its voice.