Maryland’s Dream Act, if approved by voters on Nov. 6, would lure more illegal immigrants to public colleges and cost more than state analysts have predicted. But over decades the measure’s “net benefits” could far outweigh costs, returning tens of millions to the state for each class that earns advanced degrees, according to a new study.

The report, by the Maryland Institute for Policy Analysis and Research at the University of Maryland Baltimore County, is one of the most ambitious attempts to fill in the blanks on Question 4, the Maryland ballot measure whose costs and effects are among the least well understood. It concludes that some 435 students in each graduating class would take advantage of the Dream Act to attend college. About 185 of those would be induced to graduate from Maryland high schools because of the law.

Maryland’s General Assembly approved the state’s version of the Dream Act in 2011, but opponents successfully petitioned it to referendum – a first in the state in 20 years. The law would allow illegal immigrants to pay in-state tuition rates at Maryland community colleges. Students who complete course work at community colleges could continue on to Maryland four-year colleges and universities at in-state rates. To be eligible, the student or his or her guardian must file state tax returns; the student must also have attended 3 years at a Maryland high school and file an application to become a permanent resident.

“Even if the only consideration is the fiscal effects on state and local governments, the net economic effects of the Maryland Dream Act will be positive,” write the study’s authors, economics professor Thomas Gindling and public policy professor Marvin Mandell. “The initial costs of the investment in education will be more than offset by increased tax revenues and lower incarceration costs from a more educated citizenry,”

Gindling and Mandell estimate that each class could eventually return $66 million in economic benefit to the state, including personal income tax payments. .

To reach that number, however, the authors rely on a two major assumptions: First, they assume every student who obtains a degree from a state college and university under the law will remain in Maryland for the duration of his or her working life. Second, they figure that illegal immigrants will be legal residents upon graduation and therefore have the same lifetime earning potential as U.S. citizens.

Gindling explained the latter assumption in an e-mail. “We did this for several reasons. First, any student who takes advantage of the Maryland Dream Act is required to apply for legal status. We assume that by the time he or she graduates the matter of legal status will be resolved.

“Also, if the Federal Dream Act is passed then these students will be legal residents when they graduate. In the short term, President Obama’s recent executive order that undocumented students who graduate from college are eligible for legal residency in the United States makes it more likely that students will be legal residents of the United States at graduation from college. Mitt Romney has not said that he will rescind this order. Given this background, the assumptions that we made seemed more reasonable than any alternative assumptions,”Gindling wrote.

In all, the study estimates that at any one time there would be approximately 1,294 students in Maryland community colleges or universities benefiting from reduced in-state rates under the law: 869 students in community colleges and 425 in public four-year universities.

That would represent about 0.6 percent of the state’s 223,000 students in Maryland public colleges and universities, the report notes.

The cost?

About $3.6 million annually for the state, $3.6 million for county governments and $200,000 for the federal government, the study finds largely by weighing expected attendance at colleges and universities across the state. Most would attend community college in Montgomery and Prince George’s counties, the study estimates.

But the costs could fluctuate significantly if more illegal immigrants attend one college or another. At the University of Maryland College Park, for example, the annual state subsidy per student would be $10,857, compared with an annual state subsidy of $1,301 at the University of Maryland University College.

“Another potential cost of the Maryland Dream Act,” the authors write “is that it could make Maryland a more attractive destination for undocumented immigrants (and their children), who might impose a fiscal burden on state and local governments through increased spending on social protection programs and public services such as police, fire and K-12 education. However, there is little evidence in the academic literature that undocumented immigrants are attracted to states and localities with more generous public benefits.

The report finds the forethought needed for illegal immigrants to benefit from Maryland’s law would be prohibitive to emigrate for that reason alone:

“The family would need to decide at least three years before high school graduation to move to Maryland, and once in the state would need to make sure that the student spent a minimum of three years in, and graduated from, a Maryland high school (as well as paying state and federal income taxes for all years).”