Starting with the 2013-2014 school year, the Idaho State Department of Education has adopted a four-year adjusted cohort graduation rate. An adjusted cohort tracks 9th graders through all four years of high school. The cohort is adjusted to account for students who move to or from another district, leave the country, or pass away. The four-year adjusted cohort graduation rate measures the number of students who graduate with a regular high school diploma in four years divided by the number of students in the adjusted cohort.