A college education has never been more valuable or necessary, and the link between early childhood education and later academic achievement has now been firmly established.

So it’s no surprise that parents with means are spending more time and money preparing their children for each grade level, starting before the first day of preschool, and setting them up for a better chance at a bright future.

But this ability to heavily invest in the education of their child, and the inability of others to do the same, is further widening the gap in educational success between high- and lower-income students.

The growing achievement gap threatens the viability of the workforce here in Maine and across the country, and unless steps are taken to give students from all income levels roughly equal opportunities, the costs, already enormous, will continue to grow.

WIDENING GAP

In Maine and elsewhere, the gap is headed in the wrong direction.

According to one analysis, the nationwide gap in achievement between low-income students and their better-off peers is about 40 percent larger than it was 30 years ago.

The same is happening in Maine.

According to a report released last week by Educate Maine, a business-led education advocacy group, low-income students are further behind their peers than they were 10 years ago.

For example, in 2005, 22 percent of Maine fourth-graders who qualified for free or reduced-price lunch were proficient in reading, compared to 42 percent of higher-income students.

By 2013, 24 percent of low-income students were proficient, while the number for all other students had grown to 48 percent.

The gap in reading proficiency, 20 points in 2005, grew to 24 points in eight years, particularly troubling given that reading ability at that time is tied so closely with graduation rates.

The same widening gap is found in reading proficiency in eighth grade and high school, and it is even greater, at all three grade levels, when it comes to math scores.

The gap has lasting consequences. Low-income students in Maine graduate high school 78 percent of the time, compared to 95 percent for higher-income students, and go to college just 48 percent of the time, compared to 73 percent for everyone else.

That has severe consequences for the future jobs and wages for those students, as well as for their eventual use of public assistance and involvement in the criminal justice system.

STUDENT PREPARATION

It’s easy to blame schools for failing the most vulnerable students.

But it’s not that low-income students aren’t improving — it’s that they are improving at a much slower rate than their peers.

The gap has also widened under numerous education reforms and in every part of the country.

It’s likely, in fact, that the disparity has little to do with schools, but with what happens when children are out of school.

Just how well a child performs in school depends on how well they are prepared when the bell rings, and that preparation has everything to do with the time — and money — parents have to spend.

Compared to the past, all parents are spending more on this preparation.

But parents with higher incomes can, and do, spend that much more, on things such as quality preschool, tutors and other enrichment activities.

They also, in general, have more time to spend with their children, to reinforce lessons and establish good habits.

That gives students from higher-income households a head start when they begin school, one they build upon every year.

CATCHING UP

Helping low-income students to catch up while the gap is still relatively small is key.

According to the Maine Early Learning Investment Group, a full-time early education program from birth to kindergarten would help low-income students begin school on par with their peers, and could raise high school graduation rates for low-income students by 18 percentage points.

Fortunately, Maine will have universal voluntary preschool by the 2017-18 school year.

Better policies on maternity and paternity leave and child care would give low-income parents a better shot at preparing their young children for school, too, and summer programs can keep the gap from widening when students are away from the positive influences of school.

It’s no small matter. Half of Maine public school students are now lower-income, and they are falling behind each year.

If Maine is to have a highly educated, 21st-century workforce, and if it is to lower its residents’ dependence on public assistance, we cannot afford to leave that many students behind.