It’s a path ingrained in us: Go to a university right after high school and graduate in four years. But that couldn’t be further from reality. And until education leaders take that into account, too many students will lose out.

The fall after I graduated from high school, I took the traditional path. I entered a competitive, private four-year college, and four years later, I earned my bachelor’s degree from that same institution. When I think of the route my children might take after high school, I can’t help but picture something that looks a lot like the one I took.

That makes me part of the problem with higher education today. If you randomly stopped 100 adults and asked them to raise their hand if they had received their BA, and done so four years after graduating from high school, guess how many would? I guarantee your estimate would be too high. By a lot.

A while back, Gerald Chertavian, a successful businessman turned education reformer, posed that question to a gathering of 400 education officials and public-policy people at a New England Board of Higher Education summit. When he asked who in the crowd had a college degree, just about every hand in the room went up. When he asked how many had earned that degree four years after high school, about 80 percent of the hands stayed up.

Then he lowered the boom: All these people charged with shaping education policy were far outside the mainstream. Census data from 2005 tell us that only 28 percent of American adults have a bachelor’s degree. As for how many adults took the “traditional” path and received their BA within four years of high school, some rough number crunching of federal education data shows that the percentage dips to below 10 percent. By definition, that’s no longer traditional. It’s radical, and it makes you wonder why we still call them four-year colleges.

Why are our perceptions so out of step with reality? Probably because the old path still dominates at name-brand private colleges, and they continue to be the prism through which so much of higher education is viewed.

“American elites, whether in education, politics, business, or the media, tend to focus on a small number of elite institutions and ignore the large number of institutions where the vast majority of college students are enrolled,” says Terry Hartle, senior vice president of the American Council on Education, a higher-ed advocacy and research group based in Washington, D.C. “We tend to underappreciate the complexity and diversity of higher education.”

True, the four-year graduation rate — regardless of student age — is higher at private colleges (54 percent) than public colleges (32 percent). And the rate climbs a good deal higher at elite private schools. But to get an idea of scale, consider this: If you add up the undergraduate students at all of the Ivy League colleges, you get about 60,000. Then compare that with the roughly 40,000 undergraduate students just at Ohio State University’s main campus. Or the 6.6 million students in community colleges across the country.

Hartle knows this as an education leader who’s spent years sifting through data. And he knows it as a dad whose daughter spent three years at a community college before transferring to Northeastern University.

Today’s truly “traditional” path is a goulash of enrollment patterns — frequent starts and stops, serial transfers, and oscillation between full- and part-time student status. People who study enrollment even have a term to describe these circuitous routes that students are increasingly taking, such as hopping from a two-year college to a four-year college and then back to a two-year college, with a couple of timeouts in between. They call it “swirling.”

Fluidity is the defining characteristic of today’s college student. Things promise to get only more fluid as the recession forces more people to consider lower-cost alternatives like community colleges and part-time status. But our rigid higher-ed system fights with this fluidity, making it hard for many students to adapt to college life and making the transfer process more complicated than it needs to be. The cost is lost credits, time, money, and opportunity. The fact that transfer students are typically not counted in federal graduation-rate data only strengthens the argument that public policy is operating from a distorted sense of reality.

President Obama has vowed to lead the nation toward having the world’s highest proportion of college graduates by 2020. Depending on what stats you look at, that could be quite a climb. Right now, we clock in at the 10th spot, and we have one of the highest college dropout rates in the industrialized world. But we’ll have a much better shot at getting to the mountaintop if we stop thinking there’s just one route leading us there.