Allowing kids to start public school a year or two earlier, say age 4, is a good idea. Not only will that help in the children's social development, but also parents will be able to go to work without paying for a baby sitter.

The placement of 4-year-olds in private preschool programs is already a reality in many places, and public schools in more than two-thirds of the states offer prekindergarten programs.

But the pitfalls to this early push are also realities that should be dealt with immediately.

In a study of the trend toward earlier entry into the school system, Evelyn K. Moore, executive director of the National Black Child Development Institute, notes that the primary force fueling the movement is the needs of working mothers.

The problem is that parents are not doing enough to make sure that school systems change as the needs of society change.

"First, the public schools do not have an impressive track record of supporting the achievement of school-aged children," Moore writes. "Today, 40 percent of minority youth are functionally illiterate. Black children are three times as likely as whites to be placed in educable mentally retarded classes, where they make up 40 percent of all children.

"Finally, only 20 percent of black high school seniors go on to college. This is not an impressive foundation on which to build new programs for black preschoolers."

The number of 3- and 4-year-olds in school has doubled since the 1970s. And Moore believes that the number will increase, expecially for black children.

"Almost half of black mothers with jobs outside the home still leave their preschool children with relatives," Moore writes.

"But that system is in the process of change. Young black women and their families are losing their traditional family support system for child care. Their mothers and grandmothers, the women who used to be baby sitters, are now more likely to be in the paid work force."

So what are parents to do?

Moore offers several "safeguards" that parents should push for.

For example, personnel should be hired to organize a parent education component within the preschool. Special consideration should be given to programs for fathers, teen-aged parents and parents of the handicapped.

Also, as far as predominantly black preschools are concerned, children should be provided with role models in the learning environment who are representative of their racial and ethnic makeup, for it is often through these role models that children's aspirations and goals are set for life.

The curriculum for the 4-year-old should not be a watered-down version of the first grade, Moore says. Rather, it should reflect an appreciation and enjoyment of the energy of 4-year-olds, their imagination, their curiosity, sociability and creativity.

It should go without saying, but unfortunately it needs repeating time and time again: Public schools that house programs for the very young should meet the health and safety standards that apply to independent preschools.

Good performance in school and a well-adjusted school experience depend in part on a well-nourished, healthy body.

Thus, good foods should be properly served -- preferably family style, with children learning to serve themselves under adult supervision.

Moore cautions that there is no need for testing preschoolers. Any assessment of the child's progress and behavior should be used to facilitate the learning experience by creating a more conducive environment, never to determine "graduation" or to stereotype a child. These assessments can simply be shared with the parents.

Moore notes that these guidelines could serve as a means to begin establishing a preschool program where parent and child obtain the maximum benefit. They are suggestions that surely have their costs in time and money.

But as the man says in the oil commercial: You can begin to pay now, or pay much more later.