New Jersey's Tuition Aid Grant program, which has provided nearly $1.4 billion to help low-income students attend college in the past five years, may be one of the state's most successful efforts in changing young lives.

Or it may not be making much difference at all.

We just don't know.

It is difficult to make any assessment of the program's effectiveness because no one keeps track of how many TAG recipients actually earn college degrees.

Without that information, it's impossible to know whether a program that cost the state more than $300 million for the 2012-13 school year is helping these students launch careers and build better lives.

We also don't know which colleges are doing a good job of helping TAG recipients achieve academic success and which ones aren't.

As many as 74,000 students at New Jersey community colleges, four-year public colleges and private colleges will utilize the grants this year. At both Richard Stockton College and Rowan University, more than a quarter of students are TAG recipients.

But, as Press staff writer Diane D'Amico reported Sunday, the state Higher Education Student Assistance Authority, which manages the grants, doesn't gather graduation data, the clearest indication of whether the money is being well spent.

Of course, the point of programs such as TAG is not to guarantee a degree, but to provide access to higher education for students who might not otherwise have it. (Certainly, we should remember, 100 percent of students who do not attend college do not graduate.)

But a little bit of college doesn't necessarily benefit students, at least not financially. Because many undergrads who get grants also take out loans, students who don't earn degrees may find that they have simply added to their debt and are no closer to a career.

And taxpayers have a right to be frustrated at the amount of money that is spent on students who never come near completing a degree. In a 2010 report, the American Institutes for Research estimated that $172 million in state and federal aid was spent in New Jersey during a five-year period for students who dropped out after their first year of college.

More important, in this time of tight budgets and fierce competition for public dollars, it will be difficult to defend even worthwhile programs if they cannot demonstrate their effectiveness.

The state should require colleges that accept TAG funding to keep track of recipients' graduation rates. And it should use that information to improve and focus this program so that the state - and our students - get the most for the money.