The Obama administration is proposing to make community college free for as many as 9 million students nationwide, with a plan modeled on a new program in Tennessee launched by the state’s Republican governor.

The White House says the policy would save students about $3,800 a year on average. But the viability of such a proposal hinges on the question that many U.S. community colleges are struggling with, as the New York Times reported: Even if you get students in the door, can you get them to graduate -- and with degrees that lead to good jobs?

As Mark S. Schneider, former head of the National Center for Education Statistics, puts it: Once students enroll, “Do they come back? Do they progress? Do they complete? Do they succeed?”

Under the Tennessee program, “We don’t know the answer to any of those questions,” says Schneider, now a vice president and institute fellow at the American Institutes for Research, as well as the president of College Measures, a startup that analyzes student success in the labor market.

In the U.S. economy, a college degree has high value, as quantified in a piece published by the Federal Reserve Bank of New York, and the president’s policy is aimed at bringing more people into the middle class, improving the labor force and encouraging states to boost their shrinking investments in public higher education. But for it to work, states and administrators would have to revamp a system where students are often hindered by dead-end remedial courses and by a lack of student services geared at college completion.

Some experts worry that the policy’s emphasis on free tuition, regardless of financial need, could also detract from grant assistance for low-income students. “The question remains about whether giving free tuition to students who can afford their tuition is the best use of resources,” says Debbie Cochrane, research director at the Institute for College Access and Success, or Ticas.  

Some 7.7 million students nationwide are enrolled in community colleges, and less than one-half -- 3.1 million -- take a full-time course load, according to the American Association of Community Colleges. The population of students splits roughly into two camps, those who pursue technical training, and those who are studying for liberal-arts degrees, many of whom intend to use their community-college credits as stepping stones to four-year degrees, Schneider says. 

To be sure, students who obtain associate degrees or certificates in career- or technical-oriented fields, such as health care and manufacturing, tend to do well, he says. 

“My axiom is, if you come out of a community college and you know how to fix things, or how to fix people, you win,” Schneider says. His research has shown that in Texas a student who completes a program in quality control and safety earns $73,000 annually 10 years out of school and a student who finishes a program in industrial-production technologies makes $80,000 a year a decade after graduating. By comparison, the U.S. median household income stood at $51,939 in 2013, according to Census Bureau statistics.

“A technical-training degree can put you squarely in the middle class,” Schneider says.

However, liberal-arts studies at the community-college level have proven much more problematic for students: Among those who enrolled at two-year public schools in 2006, just 15 percent graduated with degrees from four-year schools within six years, a study by the National Student Clearinghouse Research Center found.

Community colleges, with their open-admission policies, serve a challenging population of students, such as those from low-income families or those who are the first in their families to go to college. Many are parents or are working full-time. “All of these are risk factors known to decrease the odds of success, and many community-college students have multiple risk factors,” Schneider says.

Being able to cover everyday costs such as for rent, food and child care can make the difference between attending class or not, between carrying a full course load or taking longer to graduate on a part-time schedule. That is why, Cochrane says, it’s important to continue to make grant aid available -- and to make more students aware of it, even if tuition is covered.

She draws a parallel between the White House proposal and California’s “historical focus on low tuition and tuition waivers,” which she says has produced unintended consequences. The state continues to see “sky high” part-time enrollment rates among students, while they are also leaving large sums of federal student aid on the table -- approximately half a billion dollars in 2009-2010, Ticas found. “Students and colleges focus more on those tuition costs than thinking more holistically about the entire cost of being a student,” Cochrane says.

At the same time, Schneider says: “Community colleges have to improve their game. And they know it.” That means improving student services, such as career services, as well as “remedial education” offerings -- the basic math and English courses that students have to pass to advance. According to a 2012 report by Complete College America, about 50 percent of students entering two-year colleges have to take remedial courses, yet only four in 10 of those students actually complete the classes.

Creating capacity for all the students who would want to attend community college -- for free -- is another question. In recent years, budget cuts in states such as California have kept some students out of the public school system, driving them to more expensive, for-profit colleges instead, as the Huffington Post reported.

In Tennessee, state officials are not overly concerned about capacity at the moment, according to Emily House, director of research at the Tennessee Higher Education Commission.

Nearly 60,000 high-school students signed up for the free-tuition Tennessee Promise program by the state’s Nov. 1 deadline. But state officials expect only about 12,000 of them to enroll in classes come next school year, House says, because some will choose to attend school out-of-state or will elect to enroll at a four-year institution.

Others, House says, will not ultimately meet the program’s strict eligibility requirements: Between now and August, Tennessee Promise enrollees will have to meet twice with an assigned mentor and complete eight hours of community service. They also must have completed the free application for federal student aid by Feb. 15.  

As for getting community-college students to actually complete those degrees, “I think we’re grappling with it the way many states are grappling with it, and we want to improve,” House says. 

While Tennessee’s technical colleges enroll close to 30,000 students and boast an 80 percent graduation rate, the same is not true of the community-college system. Among the 75,000 students who attend community colleges, about 30 percent graduate within six years, House says. But among students enrolled full-time, the graduation rate is 68 percent.

And, under Tennessee Promise, students have to enroll full-time to receive funding. “The hope is that that will contribute to greater completion,” House says.