ALMOST every time I interview Mayor Nutter on the issues du jour on my radio program, we swerve into an update on his vision of a Philadelphia with a greatly increased college-educated population. It's obvious that education is not just policy for the mayor, it's a passion.

Some call this agenda elitist. Others attack it as a frill with all the problems the city has. I think it's about time we address the dirty little secret that Philadelphia has one of the lowest college-graduate levels for those over 25 of any major U.S. city.

This problem not only stifles many new businesses from considering Philadelphia, but I think it even degrades the overall level of understanding of issues like the raging health-care debate.

According to the Census Bureau's American Community Survey, Philadelphia ranks only 92 out of the top 100 U.S. cities in those over-25s who have a degree, with only about 20 percent of Philadelphians having one.

In Seattle, 53 percent have one. In Oakland, Calif., it's 34 percent. Yes, Oakland. As if that weren't bad enough, in Pittsburgh, it's 32 percent. That's no typo.

How did it happen? How, in a city noted for its colleges and universities, do we have such pitiful levels?

Folks might say, defensively, "We're the town of 'Rocky.' We don't need no stinking college degree!" Atlanta and Oakland have way worse poverty levels, yet they far exceed our level of college education. And while the city sits at 20 percent, the state as a whole has a degree level of 24 percent. (We're No. 32 behind such states as New Jersey, Delaware, and Georgia.)

No one seems to know why this is. but studies clearly tell us what the results are. There is a significant correlation between educational attainment and economic success of a city.

In today's high-tech digital economy, expanding companies look at the education of a region when deciding where to locate and bring jobs. Philadelphia

can't compete in this race with a 20 percent college-educated populace.

In our last mayoral race, three out of the five contenders for the Democratic nomination weren't college grads. This just doesn't happen in other major American cities.

Besides the economic problems this situation creates, I believe it degrades the level of understanding of complex issues like the health-care debate. I maintain that in places like Philadelphia and other places, like rural areas, where college-education levels are low, the health-care debate comprehension level is also low.

This view is shared by Chester E. Finn Jr., former U.S. secretary of education. In a recent column in National Review, he broke down the amount of basic literacy, math and background knowledge needed just to analyze three paragraphs of President Obama's recent speech on health care. Finn says to follow just three short paragraphs from that address, you'd have to understand the use of the word "comprehensive" when added to the phrase "health-care reform."

You'd also have to know about Theodore Roosevelt, John Dingell Sr. and John Dingell Jr. and why Obama invoked all three. And need to know how insurance really works. And what do employers do in this realm? And what an "advanced democracy" is, and what's the point of Obama's comparison of the U.S. to other countries.

I agree with Finn. We need to know things like this to be constructive participants in modern life. Engaged citizenship requires educated citizens.

Decades ago, a high-school diploma was sufficient.

Jobs, particularly in manufacturing, were plentiful. But Rust Belt cities like Buffalo, N.Y.; Detroit; and Cleveland are a grim reminder what happens when industries disappear and the workforce is unprepared for change.

I think Nutter is onto his greatest legacy as he steadfastly tries to move Philadelphia into the education orbit of places like Pittsburgh, Seattle and Oakland.

To his critics and those who resist the cold, hard truth, I say this: Today, a college education is table stakes. Building a great city is more than highways, infrastructure and economic development. Educational capital is as important as any of those other pillars.

Teacher-turned-talk-show-host Dom Giordano is heard on WPHT/1210 AM. Contact him at askdomg@aol.com.