Valerie Strauss writes The Answer Sheet for the Washington Post.

This being Labor Day, it seems like a good time to look at the way the history of the labor movement is taught in U.S. schools. Unfortunately, it isn’t — at least, not much, and when it is, it is too often inaccurately portrayed.

State content standards sometimes ignore the movement almost completely, and textbooks either do the same thing or else treat inadequately the role labor has played in the creation of the American middle class and the raising of living standards in the country.

Why? Scholars say that the answer is largely because unions are unfavorably viewed by the business community as well as by some politicians — and that this has spilled over into the treatment of the subject in textbooks because of the political way that textbook content is approved in the states.

So how distorted are the textbooks?

A 2011 report by the nonprofit Albert Shanker Institute titled “American Labor in U.S. History Textbooks: How Labor’s Story is Distorted in High School History Textbooks,” says the answer is “a lot,” and that the problem goes back at least to the 1930s....