Each year, a staggering 1.2 million students nationwide drop out of school.

A recent report by America's Promise Alliance found that 17 of the 50 largest cities, including Philadelphia, had graduation rates below 50 percent.

Nationwide, only about 70 percent of students graduate on time. So even at many of the best schools, one-third of the students don't graduate. More troubling, the dropout numbers may not fully capture the problem.

The federal No Child Left Behind law allows states to use their own methods to calculate graduation rates. Some schools inflate numbers in order to maintain federal funding, so the dropout figures may be worse.

U.S. Education Secretary Margaret Spellings yesterday announced uniform reporting standards starting in 2012. This seems like a basic idea that should've been in place years ago.

Indeed, setting standards is a good first step, but what about attacking the dropout crisis?

School districts must begin to address what Colin Powell, the founding chairman of the alliance and a former secretary of state, calls "a catastrophe."

The alliance has called for holding "dropout summits" in every state over the next years to develop action plans. Another good step, provided the action plans lead to real action.

The Philadelphia school system does a good job of tracking students. So this much is clear: The city's dropout rate is abysmal. About 42 percent of Philadelphia students drop out, which is slightly better than the national figures.

Even worse, 76 percent of the Philadelphia students who graduated last year failed a state test in reading or math as juniors. Translation: Even the students who get diplomas aren't well prepared in the basics.

The upshot is that many students fail to graduate or leave school unprepared for work.

The average income for a high school dropout in 2005 was almost $10,000 less than for a graduate.

The more than 1.2 million dropouts from the class of 2007 - including 35,000 in Pennsylvania and 19,000 in New Jersey - will cost the federal government $60 billion in lost tax revenue over the students' lifetimes.

Fixing the dropout problem isn't easy and won't occur overnight. The problems are complex and not entirely the schools' fault. In fact, the most effective solutions to reducing the dropout rates start at home.

But some cities are doing better than others.

In New York City, graduation rates at its new 47 smaller public high schools climbed on average to 73 percent last year, from a state estimate of 50 percent the year before.

In Philadelphia, the district's 33 small high schools, each with 700 or fewer students, have better test scores, higher pass rates, greater attendance, and fewer suspensions than its 21 large high schools of more than 1,000 students.

More than a dozen states require students to stay in school until age 18, including California and Texas. Several states, including Minnesota and Maryland, are considering similar measures.

Mayor Nutter wants to reduce Philadelphia's dropout rate by 50 percent. That's a great goal, but it requires a real plan. Nutter's chief education officer, Lori Shorr, and the incoming city schools CEO, Arlene Ackerman, must make achieving that goal a top priority - sooner rather than later.