With a new school year approaching, only about 40 districts have submitted the data, mandated for the first time, for the 2011-2012 school year. About 430 districts are required to report the number of students who sustained a head injury or suspected concussion.

“It’s certainly a concern if schools are not following the law to report their numbers, because that data is extremely important to us from a public health perspective, for us to understand the number of concussions schools are dealing with,” said Neal McGrath, a neuropsychologist and clinical director of Sports Concussion New England, a Brookline-based practice that consults with schools.

The state-mandated data could highlight schools that have done a good job at preventing head injuries, suggest preventive measures other schools might employ, and also bring attention to schools that were lax in diagnosing concussions, according to experts.

School administrators and state officials say there has been confusion about reporting head injuries because the new state regulations don’t specify a deadline. That’s a problem, according to the Massachusetts Interscholastic Athletic Association, which governs high school sports for the state’s public as well as some private high schools.

“The lack of a firm stated and enforced deadline is a concern to the MIAA,” said Paul Wetzel, spokesman for the association. “All of our regulations, for instance, as you probably could guess, have strict deadlines.”

The state Department of Public Health, which wrote the concussion regulations, said it plans to tell superintendents that the deadline is this month when the state sends a checklist of several requirements soon.

Surveys conducted by the Globe earlier this year revealed dozens of suspected concussions or head injuries among students playing football, soccer, hockey, and basketball. Marshfield High School, with 19 suspected head injuries, counted the highest number among the schools surveyed in football. Girls’ soccer recorded higher numbers than boys’ soccer in the Globe survey, with seven head injuries apiece for the girls’ programs at Marshfield and Concord-Carlisle. Hockey and basketball for both genders reported lower numbers overall than the other sports surveyed.

Organized football leagues, from the NFL to Pop Warner, have taken steps to lower the likelihood of head injuries following a rash of findings that concussions can cause long-term and permanent damage.

In Massachusetts, increased awareness and public attention to head injuries is prompting some high school coaches to say they will try to limit contact in football practices, which start this month. Having comprehensive totals on the number of head injuries statewide would help researchers and coaches make other improvements, some coaches say.

“I think it will be useful in the sense that it might have coaches look at how they’re conducting practices, how they’re having equipment fitted,” said Lou Silva, Marshfield’s athletic director and head football coach, who will have his coaches limit contact during practices this year.

Lauren Smith, medical director for the Department of Public Health, said the number of reported concussions may increase in the initial phases of the state’s tracking project, in part because schools, coaches, parents, and athletes will become better educated about head injuries.

“I think we have to be prepared that over the next several years we might actually see an increase in the number of concussions that are reported,” Smith said. “That doesn’t mean that all of our hard work isn’t paying off. It may just mean people are much more aware of what concussions are and how potentially life threatening they can be.”

She said her department will not release the data the state has collected from the 40 or so schools thus far. She said she did not know when it will be available for the public.

“To look at trends we would need several years of data,” said Smith. “This will be the first time that we will have data from all schools, so we’ll just have to see what we get.”