Our research isn’t unique: As a similar study showed, state politicians also do a poor job guessing public opinion of their constituents. We found two key factors that explain why members of Congress are so ignorant of public preferences: their staffs’ own beliefs and congressional offices’ relationships with interest groups.

Aides usually assumed that the public agreed with their own policy views. If an aide did not personally support acting on climate change, he or she was less likely to think that constituents wanted action. This self-centered bias is common in other areas of life — we all tend to think that other people share our preferences. But we aren’t all charged with understanding what the public wants to ensure democratic representation.

Interest groups also played an important role in explaining congressional staffs’ errors. Aides who reported meeting with groups representing big business — like the United States Chamber of Commerce or the American Petroleum Institute — were more likely to get their constituents’ opinions wrong compared with staffers who reported meeting with mass membership groups that represented ordinary Americans, like the Sierra Club or labor unions. The same pattern holds for campaign contributions: The more that offices get support from fossil fuel companies over environmental groups, the more they underestimate state- or district-level support for climate action.

Since most congressional offices cannot regularly field public opinion surveys of their constituents, staff members depend heavily on meetings and relationships with interest groups to piece together a picture of what their constituents want. And if offices hear from only deep-pocketed interest groups, they are likely to miss out on the opinions of ordinary Americans.

We should not place all the blame on Congress. The public contributes to the problem by not taking the time to express its opinions to politicians or vote. For example, recent polling shows that supporters of tighter gun regulations are much less likely to contact Congress than those who oppose gun control. Without citizen participation, it’s hard to imagine how political staffs can accurately gauge public attitudes in their districts and states.

The forthcoming midterm elections are an important opportunity for the public to make its policy choices clear to Congress. But political action can’t end on Election Day. Citizens need to keep writing, calling and meeting with elected officials and their staffs long after the midterms. Otherwise, Congress will continue to misunderstand the public’s preferences. And if Congress doesn’t know what the public wants, it’s hard to imagine it will do a good job representing all Americans.