Purdue has made very impressive gains in 4 year graduation rates, but still somewhat behind Maryland,
probably due to incoming preparation, as measured by test scores, GPA etc that are higher at Maryland.
Purdue gives more students a shot at it, and does extremely well. They are comparable schools, with a bit
different geographic mix, and location is a bit different. For an OOS student like OP , four year graduation rate
may matter some for costs.
https://www.admissions.purdue.edu/academics/freshmanprofile.php