Academic departments generally determine how many graduate students they admit, or postdocs they hire, based on the teaching and research workforce they need, not on the career opportunities awaiting young scientists. Unlike companies, universities have access to unlimited temporary-worker visas. This allows universities to hire skilled lab workers and pay them very low, “trainee” wages. Postdocs are an especially good deal for professors running labs because they don’t require tuition, which must be paid out of the professors’ grants, notes Paula Stephan, a labor economist at Georgia State University, in her book How Economics Shapes Science.

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Immigrants constitute the nation’s “only shot at getting a growing economy,” because they “start more jobs than natives,” declared New York Times columnist David Brooks on Meet the Press in February. “Every additional 100 foreign-born workers in science and technology fields is associated with 262 additional jobs for US natives,” he had written in the Times, adding that “a quarter of new high-tech companies with more than $1 million in sales were also founded by the foreign-born.”

These claims, cited by Brooks and many others, arise from a body of research that has been the subject of scholarly dispute—though you’d never know it from the media coverage of this issue. The overwhelming majority of coverage presents the conclusions reached in studies like the one conducted by Duke University’s Vivek Wadhwa, who publishes widely in popular media and speaks frequently on immigration issues. About a quarter of the 2,054 engineering and technology companies that responded to Wadhwa’s telephone survey said they had a “key founder”—defined as a chief technology officer or a CEO—who was foreign-born. Extrapolating from that figure, the study credits immigrant-founded companies with employing 450,000 people nationally in 2005.

But a nationwide survey by political scientist David Hart and economist Zoltan Acs of George Mason University reached a different conclusion. In a 2011 piece in Economic Development Quarterly, Hart and Acs note that between 40 and 75 percent of new jobs are created by no more than 10 percent of new businesses—the so-called high-impact firms that have rapidly expanding sales and employment. In their survey of high-impact technology firms, only 16 percent had at least one foreign-born founder, and immigrants constituted about 13 percent of total founders—a figure close to the immigrant share of the general population. But the more fundamental problem with Wadhwa’s study, Hart and Acs suggest, is that it does not report the total number of founders at a given company, making conclusions about immigrants’ overall contribution impossible to quantify.

Evaluating the issues of statistics and sample selection that divide the academic researchers is beyond the purview of most general media, but informing readers that reputable researchers reached different conclusions is not. Though real, the immigrant role in high-tech entrepreneurship could be considerably less dramatic than many writers claim. Research on Silicon Valley entrepreneurs in 1999 by AnnaLee Saxenian, for example, found that 36 percent of high-tech companies owned by Chinese immigrants were doing nothing more groundbreaking than putting together computers for sale from components.

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As Erin Neill, of Senator Mikulski’s staff, pointed out, no one in the immigration debate speaks effectively for US-born STEM workers. The IT world’s libertarian ethos, the relative poverty among young scientists and their unemployed and underemployed peers, and a fear of antagonizing present or potential employers all hamper efforts to organize these workers. National scientific associations and advocacy groups sponsored by industry and universities, meanwhile, represent the interests of those who benefit from the system—tenured faculty, university administrators, and company executives, including those at companies whose donations support scholarly conferences and other association activities. These organizations and their lobbyists frame their policy arguments with feel-good abstractions about the inherent value of science and research and innovation, suggesting they are a panacea for America’s economic ills.

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