Argosy University-Phoenix Online Division, Rio Salado College and Northland Pioneer College have the lowest 'on time' graduation rates in Arizona, according to a Higher Education Tribune analysis of federal data.

The analysis includes the on-time graduation rates of students who began in 2010 at all four-year schools and fall 2013 at two-year schools reported to the U.S. Department of Education.

Worst 'on time' graduation rates at Arizona schools