Idaho: High school graduation rate Note: The "four-year adjusted cohort graduation rate" is calculated by the number of students who graduate in four years with a regular high school diploma divided by the cohort of students who entered school together in 9th grade, while modifying for transfer students and those students who emigrated or expired. Source: 2013-2017: Idaho State Department of Education, (https://apps.sde.idaho.gov/Accountability/ReportCard.); U.S. data: National Center for Education Statistics - (https://nces.ed.gov/programs/dropout/ind_04.asp); DATE LAST UPDATED: March 5, 2019.