The colleges with the very highest four-year graduation rates tend to have fairly small undergraduate enrollments and to spend a lot of money on their students. Catholic institutions are notable overachievers.

The university president's home at Washington and Lee University. (Courtesy of Washington and Lee University)

That’s the message from a sophisticated new Web site on graduation rates, unveiled Monday by the Chronicle of Higher Education.

We’re told on the home page of the new site that Washington and Lee University in Virginia has the nation’s highest four-year graduation rate, 91.7 percent. W&L has just under 2,000 students and spends $184,489 per “completion.”

Williams College is second, with a 91 percent graduation rate, 2,048 undergraduates and $244,104 spent per degree. College of the Holy Cross, less well known nationally, is third, with a 90.3 percent graduation rate, 2,899 undergraduates and $151,707 spent per degree.

It’s a similar story for the rest of the Top 10:

3. Princeton, 90.1% graduation rate, 5,142 undergraduates, $374,620 per degree.

4. Notre Dame, 90% graduation rate, 8,442 undergrads, $161,780 per degree.

5. Bucknell University, 89.7% grad rate, 3,508 undergrads, $153,693 per degree.

6. Vassar College, 89.6% grad rate, 2,446 students, $232,749 per degree.

7. Wesleyan University, 89.1% grad rate, 2,854 students, $170,136 per degree.

8. Yale University, 88.9% grad rate, 5,310 students, $502,748 (!) per degree.

9. Georgetown University, 88.9% grad rate, 7,579 students, $135,275 per degree.

10. University of Pennsylvania, 88.6% grad rate, 11,940 students, $264,802 per degree.

Along with the new trove of completion data - - and no one does a searchable database better - - the Chronicle has published some attendant pieces that remind the reader how limited these federal statistics really are. The federal government began requiring and collecting grad rates in the past two decades. And the way it defines a graduate (a student who starts and finishes the same school within 100, 150 or 200 percent of the allotted time) works for some, but not nearly all, students.

Why, President Obama himself would not be counted as a graduate, under his government’s formula, because he started at one college and finished at another.

The formula favors four-year residential colleges like Washington and Lee.

One thing that always surprises me when I see graduation tables is how poorly many of the top public universities do in getting students out in four years.

Two local institutions, the U.S. Naval Academy and the University of Virginia, have the highest four-year graduation rates among public universities, according to the database, at 88.1 percent and 84.5 percent respectively. The College of William and Mary ranks fourth, at 82.2 percent.

But look farther down the list, and you might be surprised to see the lengthy list of flagship-quality public universities with four-year grad rates below 60 percent: the University of Florida (59%), UC San Diego (57%), the University of New Hampshire (56%), SUNY Albany (55%), the University of Washington (54%), Rutgers (53%), the University of Texas (53%), U-Mass Amherst (52%), the University of Georgia (52%), UC Davis (51%), the University of Wisconsin (50%), Clemson (50%), Indiana University (50%), the University of Minnesota (46%), the University of South Carolina (46%), Ohio University (46%), the University of Iowa (44%) and the University of Oregon (44%).

I’ll stop at 44 percent to avoid some truly embarrassing numbers.

Big public universities fare much, much better when one considers the six-year graduation rate. Why? Students at public universities tend to pay much less to attend, and flagship university campuses are often lovely places. It’s hard to leave. In addition, students at even top flagships such as Berkeley have an increasingly hard time getting the classes they need to graduate, because of budget cuts. Many hold significant on- or off-campus jobs.

At some schools, the distance between the four- and six-year graduation rate is stunning. At Cal State Long Beach, one of the most selective Cal State campuses, the completion rate jumps from 12 percent to 54 percent in that span.

UT Austin very recently launched a campus-wide initiative to raise its four-year graduation to 70 percent, by attacking many of these root causes.

Of the 10 colleges with the largest undergraduate enrollments, only two have four-year graduation rates over 50 percent. One is often-maligned Penn State, the massive Pennsylvania flagship, which boasts one of the highest four-year grad rates in its sector, 62 percent. (That’s 10 points higher than the rate at UT Austin.)

Colleges that spend the least per degree also fare poorly, although it would be interesting to see what Wilkes University in Pennsylvania is doing to yield a 52-percent four-year graduation at a rate of $38,444 per degree.