On July 28, 2011, Senator Chuck Schumer, a democrat from New York, opened a Senate Judiciary subcommittee hearing on high-skill immigration with a call to staple a green card to the diploma of every foreign student who earns a degree in science, technology, engineering, or math—known collectively as a STEM degree—in the United States. “As we all know,” added Texas Republican John Cornyn, the subcommittee’s ranking member, “there is a scarcity of qualified people for many jobs, particularly those in high technology.”

The senators’ comments echo the conventional wisdom about America’s scientific labor force, repeated in countless media articles and broadcasts, and by business and political leaders all the way up to and including President Obama: we are failing to produce a sufficient quantity of scientists and engineers and therefore must import large numbers of foreigners to remain innovative and competitive. Just a pair of recent examples: a Washington Post op-ed on August 4, 2011, that explained how to “curb our engineering shortage” and a New York Times story on November 4, 2011, headlined “Why Science Majors Change Their Minds (It’s Just so Darn Hard),” that highlighted a call by “the president and industry groups” for “colleges to graduate 10,000 more engineers a year.”

But what “we all know,” as Senator Cornyn put it, turns out not to be true—and the perpetuation of this myth is discouraging Americans from pursuing scientific careers. Leading experts on the STEM workforce, including Richard Freeman of Harvard, Michael Teitelbaum of the Alfred P. Sloan Foundation, Paula Stephan of Georgia State University, Hal Salzman of Rutgers, Lindsay Lowell of Georgetown, and Norman Matloff of the University of California-Davis, have said for years that the US produces ample numbers of excellent science students. In fact, according to the National Science Board’s authoritative publication Science and Engineering Indicators 2008, the country turns out three times as many STEM degrees as the economy can absorb into jobs related to their majors.

So what’s going on? Simply put, a desire for cheap, skilled labor, within the business world and academia, has fueled assertions—based on flimsy and distorted evidence—that American students lack the interest and ability to pursue careers in science and engineering, and has spurred policies that have flooded the market with foreign STEM workers. This has created a grim reality for the scientific and technical labor force: glutted job markets; few career jobs; low pay, long hours, and dismal job prospects for postdoctoral researchers in university labs; near indentured servitude for holders of temporary work visas.

Here’s what Ronil Hira, an engineer and a professor of public policy at Rochester Institute of Technology, told the senators at that July hearing:

Contrary to some of the discussion here this morning, the STEM job market is mired in a jobs recession…with unemployment rates…two to three times what we would expect at full employment….Loopholes have made it too easy to bring in cheaper foreign workers with ordinary skills…to directly substitute for, rather than complement, American workers. The programs are clearly displacing and denying opportunities to American workers.

Hira’s testimony got almost no media attention, coming as it did a week before the headline-hogging debt-ceiling deadline. But for many years reporters have repeated, without scrutiny, the assertions about shortages by representatives of industries and universities that employ large numbers of STEM workers, and thus have strong financial interests in keeping salaries down.

The public perception of a dearth of homegrown talent has shaped national policy, permitting companies and universities to import tens of thousands of foreign scientists and IT workers who toil for artificially low wages.

Even more damaging, the resulting oversupply has destroyed the incentives that used to attract many of America’s best students to science and technology careers. Importing PhDs and other highly skilled workers depresses the incomes of everyone in the affected fields, according to research by Harvard economist George Borjas. Raising the supply by just 10 percent through immigration lowers pay in a given field by 3 to 4 percent, he wrote in a 2006 paper for the National Bureau of Economic Research. As it is, more than half the postdocs working at American universities are foreigners on temporary visas.

Beryl Lieff Benderly is a fellow at the American Association for the Advancement of Science.