"The dog ate my homework" and other classic fibs are legendary in classrooms across the country. When it comes to giving an explanation for a missing or incomplete assignment, students can be masters of excuses.

But children aren't the only ones playing that game. Adults have a knack for it, too. And in the case of rationalizing educational failure, some excuses are as tired as that dog with an inexplicable appetite for paper.

No doubt you've heard the one about poverty, which may be the leading excuse for academic failure. It's so common that if a school is in a low-income neighborhood, it is presumed to be low achieving. President Bush has criticized this, rightly, as "the soft bigotry of low expectations."

This defeatist outlook only reinforces -- and perhaps even deepens -- academic failure. Low-income students eligible for the federal free and reduced-price lunch program score significantly below their peers in all subjects tested by the National Assessment of Educational Progress. On the 2003 NAEP math and reading assessments, only 15% of these low-income fourth-graders scored at or above the proficient levels in these subjects.

The status quo is sobering, and the challenges are real. True, children from low-income homes may not begin life surrounded by all the educational enrichments their peers enjoy. And yes, the academic record of students from disadvantaged backgrounds typically has not been good. But should we then concede victory to the culture of victimhood and write off these children? Of course not.

Failure, we've found, doesn't have to be a foregone conclusion. A few years ago, The Heritage Foundation searched out schools serving disadvantaged students, seeking to identify examples of those defying low expectations and achieving academic excellence. We profiled 21 of these high-performing, high-poverty schools and looked for common themes in their strategies for success.

Take Cascade Elementary in Atlanta, where students continue to leave state averages in the Georgia dust. In this school, where nearly all students are black and more than three out of four qualify for the free-lunch program, 93% of second-grade students met the state standard for English language arts in 2002. The results are persistent throughout other grade levels: Eighty-eight percent of fifth-graders met the state standard.

In Chicago's George Washington Elementary, 80% of the student body qualifies for free lunches, but no one makes excuses. These students' strong suit is writing: In 1999 and 2000, a full 100% of fifth-graders met the state standard. Ninety-two percent did so in 2002. (The state average in 2002, by the way, was 59% of students meeting the standard.) Meanwhile, student scores on math and reading tests in each of those years well exceeded the state average.

What makes the difference at schools like Cascade and Washington? For starters, it takes a strong principal with vision. "What we do is not rocket science," Cascade principal Dr. Alfonso Jessie Jr. said in describing how he leads his school. He emphasizes personal attention to students, testing and basic skills, and he works closely with parents to ensure that home environments reinforce strong learning habits.

Principals at other successful schools, such as Frederick Douglass Academy in New York, had similar strategies. In fact, there were a number of common excellence-producing strategies at all 21 of the schools, including:

•  Principals are free to make decisions and innovate. 
•  Principals use measurable goals to establish a culture of achievement. 
•  Master teachers bring out the best in a faculty.
•  Rigorous and regular testing leads to continuous student achievement. 
•  Achievement is the key to discipline. 
•  Principals work actively with parents to make the home a center of learning.

The final lesson from these high-achievers is that school is hard work. There is no substitute for effort on the part of everyone involved.

The art of teaching is to move each child closer to his or her potential. The art of leading a school is to create a culture of rigorous excellence in which good teachers are challenged to thrive and students flourish as a result.

Young people tend to live up -- or down -- to our expectations of them. Let's not give them a reason to make excuses.

Jennifer Marshall can be reached through the Web site of the Heritage Foundation at www.heritage.org.