<p>The fact that Lehigh and Carnegie fail to make the list should be a huge tip-off as to one of the factors involved here. Engineering programs tend to require more than 4 years of study.</p>
<p>Student615 also has a point–some students may take a little more time to get through public universities because they can afford to. They can take some lighter semesters, try a low-credit internship, etc. Another term or two of school is not an unappealing option, particularly in an iffy job market. This is less true of the more expensive public universities, but not an unheard-of phenomenon at those places. An enrollment projection person I used to work with, who’d tracked these things for years, built this right into his model–when the economy was bad, he figured on more seniors sticking around.</p>
<p>My concern about 4-year graduation rates would focus in more on those students who wanted to graduate in four years, and who were in a four-year program, but weren’t able to get out in four years. How many of them are there? Why was that? Did they have to work a lot of hours due to insufficient aid? Could they not get into needed classes?</p>