Left-aligned industries include creatives, employees of colleges and universities, publishers, and tech workers. The oil, gas, and coal industries are ideologically skewed in the other direction, as are workers in agriculture and mining.

In his original paper, Bonica expressed surprise at the extreme political lean in certain occupations. “In some industries,” he wrote, “ideological sorting easily exceeds the levels of sorting observed along geographic or economic lines.”

Quartz also honed in on the political contributions made during 2014, the previous midterm elections. We mapped the median ideological score of an occupation’s individual contributors against their median contribution amount. We included occupations which appeared at least 1,000 times in the data.

Using the median tells only a simple statistical story, but there’s still an interesting pattern that emerges. Just over half of the left-leaning occupations had median donations under $100. On the other side of the spectrum, not a single conservative-leaning occupation had median donations under $100.

This work is a great reminder of why politicians tend to court particular industries. That hard-hat photo op isn’t just about the votes.

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