A study to be released this week by the Economic Innovation Group, a think tank in Washington that advocates policies to help economically distressed parts of the country, finds that 28 of the 70 most competitive House districts this year rank as “prosperous” — the highest quintile — on the group’s distressed communities index. Another 15 districts rank in the next quintile, “comfortable.” Those districts have higher incomes and faster job and business growth than other areas.

Only six of the most competitive districts rank as “distressed,” the lowest quintile in the index.

As a group, the 70 most competitive districts have not seen their incomes grow more, or their unemployment rates drop faster, than the rest of the country since Mr. Trump took office. But they began the Trump era in better shape than the rest of the country.

In 2017, the median household income in a typical competitive district was just over $66,000, according to the Census Bureau. For the typical noncompetitive district, it was just under $57,000. The median income for a “prosperous” competitive district was more than $73,000.

Those districts frequently run through the suburbs of large cities in high-income states. The “prosperous” and “comfortable” list includes four districts in California and three each in New Jersey, Minnesota, Florida and Texas. It also includes Colorado’s Sixth District, one of the most prosperous in the nation according to the Economic Innovation Group rankings, where the incumbent, Representative Mike Coffman, a Republican, is trailing badly in the polls.

Toss-up districts are more dynamic and diverse than the nation

The broad universe of competitive seats is wealthier and whiter than the nation as a whole, the Economic Innovation Group analysis finds. But in a narrower group of seats that could hand Democrats control of the House by themselves — those that Cook ranks as “toss up” or “lean Democratic” — the relatively high-earning population includes a larger share of immigrants than the typical district.

The toss-up districts “are by and large pretty dynamic places, where the status quo is working rather well,” John Lettieri, the president of the Economic Innovation Group, said in an interview. “Things like globalization and immigration aren’t things to be feared there. They’re woven into the fabric.”