This is a time of the year when, as the popular holiday song goes, "Mom and Dad can hardly wait for school to start again."

But parents may want to treat the end-of-year break from classes as an opportunity, rather than a challenge. They should be aware of what their children are learning in school. Problem is, they seldom have time to sit down and really look at what's being taught. Winter break is the perfect time to have that conversation with your kids.

It's never too soon to involve yourself in your children's education. After all, the problems begin early, with children who simply never learn the basic information they'll need to succeed later in life. For example, the 2007 National Assessment of Educational Progress finds that one third of fourth graders score "below basic" in reading. Not surprisingly, the numbers are even worse for children from disadvantaged families: Half the fourth graders in this category can't read.

If we want to improve these and other dismal numbers, parents must get busy, because the system isn't set up to hold schools or teachers accountable. Consider teachers' unions. They tout themselves as part of the solution. "We're 3.2 million members working to provide great public schools," the National Education Association asserts on its Web page.

Yet "every time someone wants to inject a little choice into the equation for the benefit of the kids, inject a little freedom, inject a little competition," former Sen. Fred Thompson recently noted, "the NEA is there to oppose it and bring in millions and millions of dollars to go on television and work and scare people and misrepresent the situation on the ground."

That's what happened recently in Utah. The NEA poured more than $3 million into its campaign against Referendum 1, a measure that would have allowed parents to decide where to send their children to school.

Teachers' unions oppose school choice because they're frightened it might work. But while they've been fighting to keep children trapped in under-performing public schools, school choice has been quietly spreading.

Today, 13 states and Washington, D.C. have school-choice programs. Thanks to these programs, as many as 150,000 children have been given the chance to attend private school this year. And the good news is that school choice works. University studies show that voucher programs improve parents' satisfaction with their children's schools and boost test scores. Thanks to this success, school-choice policies are attracting more bipartisan support. In recent years, school-choice plans have been implemented in Arizona, Iowa, Pennsylvania, Rhode Island and Washington, D.C.

These programs are working because they're getting parents involved. For example, vouchers allow parents to shift their children out of failing public schools and into charter or private schools. The availability of options allows these children to get a better education at a more responsive school.

Plus, school-choice programs promote competition, which seems to be the only thing that inspires public schools to get better. A few years ago, Harvard University economist Caroline Hoxby studied the effect of a voucher program in Milwaukee and found that public schools that faced competition improved more than schools that enjoyed a monopoly. As with any business, the threat of losing "customers" forces schools to do better.

It's time for more candidates to call out the teachers' unions over their opposition to school choice. And it's time for more parents to discover what their children are learning.

Our children should be studying the founding documents of our country, such as the Declaration of Independence and the Constitution. But unless you ask, you'll never know whether your children are studying the principles of government articulated by the Framers or if they're being taught that Washington, Jefferson, Madison and company were just a bunch of slave-owning white guys.

When informed parents get involved, they can make a big difference. They can pressure failing school systems to do better, especially if they have the power to pull their children out of those failing schools. School choice can pave the way.

Ed Feulner is president of The Heritage Foundation (heritage.org).