It is? I'd like to see some data/backup for that stat.
Probably because most engineering courses take 5 years. The 5 year graduation rate would be more revealing.
The diagram down the page at this link seems to refute the 19%
https://www.collegefactual.com/colleges/california-institute-of-technology/academic-life/graduation-and-retention/
Probably means to say Cal State.
The College Scorecard reports the CalTech graduation rate for 2014 was 92.3%
Maybe that is for the ones who are remedial students allowed in for diversity purposes
It looks like the commonly cited 80% Caltech four-year grad rate excludes incoming students who fail to complete required remedial courses, and it of course it excludes students that take longer than four years but still graduate. The remedial courses are not for college credits.
Very few students finish college in four years. Most students change their majors at least once. The average at most schools is over five years to get a degree.