The best of intentions are only as good as the actions that follow.

That’s a lesson the Suffolk School Board is learning as it wrestles with the problem of more than 50 percent of the city’s seniors missing a key, new ingredient to their graduation requirements: community service.

When members of the School Board approved the new requirement in 2012, their intentions were admirable: Teach students about the importance of giving back to the communities where they live, give those students a chance to add a distinctive touch to their college applications and help improve the lives of others in the process.

But four years later, less than half of the city’s senior class has completed the 50 hours of community service students are required to have in order to graduate.

One of the objections raised during the initial discussions about the new requirement was that compelling students to go out and do good things is an ineffective way of teaching the value of selflessness. At best, the argument was made, many teens would volunteer simply because they had to do so.

Sadly, that’s exactly the situation in which many now find themselves. Having failed to spread their service across their high school careers, as they’d been encouraged to do, these students now have fewer than six months to rack up the volunteer hours they need to graduate.

As predicted, the school system’s suggested solution will do little to instill a sense of altruism in those students who will now find themselves cleaning cafeterias and picking up litter around their schools during the course of the next few months. For many of them, the duties will feel more like a court-imposed “community-service” sentence than a life-changing lesson in volunteerism.

That’s too bad, but it’s not all that surprising. Considering the low rates of volunteerism among American adults, what would have been more surprising would have been a high rate of completion of this graduation requirement without the benefit of constant nagging by administrators, guidance counselors and parents.