IT’S NOT EXACTLY surprising news that the public benefits of providing a college education for thousands of ambitious students, even after factoring in state and local subsidies for tuition, net out to many millions of dollars annually. Nonetheless, a solid new study confirms that proposition, and the timing is useful. It comes just weeks before Maryland voters will determine the fate of a ballot measure on the state’s Dream Act, which would provide in-state college tuition rates to children of undocumented immigrants — children who graduate from Maryland high schools and fulfill a list of other conditions.

The report by the Maryland Institute for Policy Analysis and Research at the University of Maryland Baltimore County totes up the Dream Act’s projected costs and benefits. The conclusion: Maryland would get an incredibly good deal by subsidizing college educations for the children of undocumented immigrants who were brought to America at a young age.

How good a deal? At a conservative estimate, the study’s authors estimate that each year’s class of the students in question — specifically, those who go on to college, enticed by the same tuition subsidy granted to their American-born classmates — could eventually yield $66 million (in 2011 dollars) in economic benefits to society. That includes not only increased lifetime earnings for the students themselves but also higher sales, income and property tax payments as well as public savings from a lower rate of incarceration from a better-educated citizenry.

Of that amount, the annual net benefit to local, state and federal government coffers is estimated at about $24 million — $18 million for the federal government and $6 million for the state and local governments.

Those findings are all the more impressive given that relatively few students are estimated to be likely beneficiaries of the Dream Act. About 1,300 undocumented young people would be enrolled in state community colleges or universities at any one time — just 0.6 percent of Maryland’s overall enrollment in public colleges and universities.

Maryland’s Dream Act makes all the more sense in light of the Obama administration’s recent move to grant temporary work permits for the children of undocumented immigrants who have finished high school and have no criminal record. Together, those measures provide the beginnings of an institutional structure that Dream Act youngsters with drive and talent might use to fulfill their potential and contribute to the country where many have spent the great majority of their lives.

It is self-defeating folly for Maryland, or any other state, to educate students through high school, as they are required to do by law, then deny even the most promising among them further opportunities. Marylanders hardly need an academic study to explain the benefits of a more highly educated citizenry. As long as they have such a study, though, it should settle any lingering debates about the merits of the Dream Act, a surefire investment in the state’s economic prospects.