They have experienced difficulty regarding the rates at which students receiving Federal Financial Aid graduate - i.e. their issues are based on low graduation rates and not based on being a diploma mill.
Disclosure: my spouse teaches for UoP part time.
UoP had about 400,000 students at the time the Frontline piece was produced - that's seven Ohio State Columbus's [http://www.osu.edu/osutoday/stuinfo.php] so number of schools is not perhaps the best measure.
Rightly or wrongly, because UoP has open enrollment they admit more students who are eligible for Federal Financial Aid than most schools because of the population they enroll.
And nothing in the Frontline piece accused UoP of being a diploma mill as was implied by the prior comment to which I responded. A criticism of their business model is a different indictment altogether.
Wait, so just like a real university?