EDITORIAL : TO FOIL YOUTH CRIME; MANY OF THESE CRIMES COULD BE PREVENTED THROUGH EARLY INTERVENTION.

SOME of today's children will become tomorrow's young criminals.

Numbers tell the story.

Population statistics show clearly the number of juveniles and young adults will increase in the coming decade.

Teen-agers and young adults traditionally commit a disproportionate amount of crime, including an enormous amount of violent crime.

So the crime rate will increase unless something is done to prevent juvenile crime.

That's a disappointing forecast for California, which has enjoyed a falling crime rate recently. One reason for that decline is the graying of the baby boom generation.

Instead of burying our heads in the sand and ignoring the looming challenge of juvenile crime, Californians can do something in advance of the problem.

The most expensive way of responding is to do nothing and hope the problem goes away.

A better policy is to re-examine youth programs, replacing or improving ineffective ones and rededicating public support for the ones that work.

After-school programs, Boys & Girls Club activities, local Police Activity League centers and a host of others are good examples of what communities can do - and are doing - to steer youths away from trouble.

The public should rally behind such endeavors that emphasize responsibility, good behavior and achievement inside and outside the classroom.

The public can support them and get involved, whether through providing money and other resources, donating time to assist the programs directly or indirectly, or simply voicing approval.

Intervention programs are not the whole solution to juvenile crime. But they are a part of it.

Incarceration alone isn't enough.

Already, a lot of public money and effort has been spent on crime reduction - much of it devoted to law enforcement and prisons where those who commit crimes can be locked away. Tougher laws, such as the state's ``three strikes, you're out'' law, also have made an impact.

But more can be done now on other fronts.

A 1996 Rand Corp. study indicated that crime could be reduced further through parent training, graduation incentives and supervision of delinquents. To find out if those efforts really would work, as the study suggested, would require demonstration projects costing millions of dollars.

Without waiting for demonstration projects, the public already can boost programs such as the after-school activities already mentioned.

Mentoring - teaming a youngster with an older person to serve as a friend and adviser - is another way.

This month, Gov. Pete Wilson submitted a state budget proposal calling for $40 million in juvenile crime prevention programs, including a $6 million expansion in mentoring programs.

Even without waiting for a mentoring invitation, members of the public can seek and support activities in all those worthy areas - mentoring, after-school programs, better local schools and expanded parent education to help youngsters avoid trouble.