<p>Bclintok, I think your observation about the great differences among public universities is very apt and wonder what the explanation would be, not just for retention, but for graduation rates.</p>
<p>Your earlier observation, however that “Assuming that 4 years to degree is the norm…works for most LACS with their relatively simple, standard-issue 4-year curricula, but it just doesn’t reflect the complex realities of undergrad education at major research universities” requires more support. The list above is filled with major research unviersities with very high 4 year graduation rates. In addition, the curricula at the LACs I have seen were not simpler than the curricula at the major research universities I attended and, in many cases, there are more requirements to fulfill, which often causes students to take an extra year. </p>
<p>In addition to the correlation between selectivity and retention, it would be useful to see whether the percentage of low income; first time college students; and students new to America correlates with retention and 4/6 year graduation rates.</p>
<p>Your reference to students in 3/2 engineering, 6 year BA/MD, etc programs is helpful, although that percentage of students may be small–and are you sure that the students in, for example, 6 year BA/MD or 5 year BA/MBA programs are not counted among 4 year graduates?</p>