The teacher boycotts making national headlines highlight the problem with the way many define class in the United States — especially “working class.”

The walkout in Oklahoma is part of a wave of educator revolts in states where tax cuts have drained state funding for schools, The Washington Post's Moriah Balingit reported. The teacher protests there, in Kentucky and elsewhere were inspired by West Virginia teachers, who won a 5 percent raise after a nine-day strike, emboldening frustrated educators across the country.

But a lack of understanding about education and income often make addressing the economic woes of Americans like these teachers challenging.

In the aftermath of the 2016 presidential election, analysts often conflated the working class with those who don't have a college degree. Debates over economic anxiety dominated conversations as observers attempted to understand why a billionaire with an Ivy League education won white working class voters in Middle America during the 2016 presidential election. Sixty percent of white Trump voters did not have college degrees.

But the teacher walkouts are a reminder that even professionals with master's degrees in some of the country's largest cities endure many of the same economic challenges associated with those in blue-collar jobs. This is perhaps why most — 54 percent — of white working-class Americans said investing in college education is a risky gamble, according to a survey by the Public Religion Research Institute and the Atlantic.

According to data from the Bureau of Labor Statistics, the average salary for elementary and middle school teachers is $56,420 per year, while high school teachers earn an average of $58,170. The salary is comparable to that in some trade jobs, like plumbers ($57,070), electricians ($57,910) and food service managers ($57,250).

Law professor Joan C. Williams, author of “White Working Class: Overcoming Class Cluelessness in America,” wrote for Time: “Class should not be determined by income alone.”

“In our definition of the missing middle, we included American households with high incomes but no college graduate,” Williams wrote. “Why? Because while class is highly correlated with income, it’s expressed through cultural differences of which graduating from college is the single most important example.”

This is important in attempting to comprehend how President Trump performed in 2016. Because although Trump did not win the votes of the poorest Americans, he performed best among voters earning between $50,000 and $100,000. Or as Williams calls them, the “have-a-littles, not the have-nots.”

It's worth remembering while looking forward to midterm elections, in which boycotting teachers have promised to vote against those who don't address their economic demands.

Thousands rallied at the Oklahoma state Capitol building during the third day of a statewide education walkout April 4 in Oklahoma City. (Scott Heins/Getty Images)