Yet, little research has examined whether Congressional staff actually recognize thepreferences of their Members’constituents. Using an original survey of senior US Congressionalstaffers, we show that staff systematically mis-estimate constituent opinions. We then evaluate the sources ofthese misperceptions, using observational analyses and two survey experiments. Staffers who rely moreheavily on conservative and business interest groups for policy information have more skewed perceptionsof constituent opinion. Egocentric biases also shape staff perceptions