Proponents and skeptics of the U.S. system for granting visas to high-skilled workers released dueling studies in Washington as the Senate began what is going to be a two-week debate on immigration reform that will extend beyond Memorial Day.

Since a bipartisan group of senators agreed to a comprehensive immigration bill on May 17, critics have assailed the proposal from every angle—with most of the focus on low-wage immigrants.

But technology companies that say they need to hire high-skill foreign nationals to remain competitive have their own beef with the measure. Although it raises annual H-1B visa limits from 65,000 to 115,000, with a provision to increase them to 180,000 based on demand, employers assert that the bill doesn’t go far enough.

H-1B visas allow an immigrant with a bachelor’s degree or higher to work in the U.S. for up to six years. Policy toward high-skill immigration is included in a massive Senate bill that is now the foundation for debate in that chamber that began May 21 and will continue until after the congressional Memorial Day recess.

In addition to implementing an H-1B ceiling that is too low, advocates say the Senate bill hurts companies utilizing the visa by subjecting all of them to labor-market and prevailing-wage tests that now only apply to companies primarily dependent on H-1Bs or have willfully violated H-1B laws.

On May 21, the National Foundation for American Policy released a study that found no evidence of increased H-1B abuses. Back wages associated with enforcement of H-1B rules declined from fiscal 2005 to fiscal 2006 to $4.6 million. And 90 percent of violations were for “paperwork offenses.”

The study also showed that 57 percent of H-1B professionals had a master’s degree or higher level of education and that they didn’t decrease wages or increase unemployment for U.S. high-tech workers.

Companies say they use H-1Bs to recruit math, computer science and engineering employees. They also point out that the majority of science and technical graduates from U.S. colleges are foreign nationals.

“We’re just not producing enough experts in those fields in the U.S. system,” says Bo Cooper, an employment attorney at the law firm Paul Hastings in Washington.

A different study, released May 22 by the Center for Immigration Studies, shows that H-1B computer workers are mostly low-skilled and work for wages that average $12,000 less than the median wage for U.S. workers doing the same job in the same place.

“[I]t is clear that the H-1B program is rarely being used to import ‘highly skilled’ computer programmer workers,” wrote author John Miano, founder of the Programmers Guild. “Either the H-1B program is used primarily to import relatively less-skilled, entry-level or trainee workers (and thus is of dubious value to the American economy), or employers are lying about these workers’ skills in order to suppress their wages.”

Both sides of the H-1B debate are finding something to oppose in the Senate immigration bill. Beyond the H-1B changes, the Senate measure also would transform the U.S. immigration system from one that is driven by employer demand and family reunification to one that would allow immigrants to apply for entry based on their talent. In that approach, companies no longer call the shots on who can work in the United States.

“There’s a loss of control over the kinds of skill sets that get presented to the system and approved,” Stuart Anderson, executive director of the National Foundation for American Policy, said in a press conference call. “The bill is pretty much a disaster for high-tech employers.”

Those companies are lobbying the Senate to exempt from H-1B and green card caps professionals who have earned a master’s or higher degree from a U.S. university. They also want the existing set-aside of 20,000 H-1B visas for master’s degree and higher employees to apply to those who have earned their degrees from foreign institutions.

High-tech companies are sending an urgent message to senators.

“The limited increase in H-1B numbers combined with the new enforcement and attestation requirements for all H-1B participants are likely to make the program more expensive to implement and less effective as a tool to recruit foreign-born professionals to fill jobs available in the U.S.,” Robert Hoffman, vice president of government and public affairs for Oracle, said in an e-mail interview. “Oracle and many other multinational tech companies would be forced to consider shifting a portion of their development work to countries that have more flexible immigration policies.”

But a skeptic of the H-1B system says safeguards are too weak to ensure that a prevailing wage is paid to H-1B workers and the labor market is tested to prevent U.S. applicants from being denied jobs.

“It’s critically important that this gets fixed,” says Ron Hira, an assistant professor of public policy at the Rochester Institute of Technology and a research associate at the Economic Policy Institute. “The Senate bill fixes only some of the flaws, not all of the flaws.”

Immigration advocates will have a greater opportunity to influence the Senate measure now that Senate Majority Leader Harry Reid, D-Nevada, has agreed to extend the debate into June.

“A longer period of time lends itself to more thoughtful consideration of changes to the bill,” says Mike Aitken, director of government relations for the Society for Human Resource Management.