Title: Do GPA subjects differ in difficulty? A Rasch perspective on Norwegian lower secondary school graduating assessments
Abstract: Graduating from lower secondary school (grunnskole) presents young Norwegians with major life choices between continuing onto academic tracks in upper secondary schools, onto vocational training, or directly into the labour market, often in heavy reference to their grade point averages (GPA). This study investigates whether the subjects constituting the GPA calculation differ in difficulties by applying Rasch models to the 2019 grunnskole graduates' academic records. IRT results showed overall differences in subject difficulties, with mathematics being the most difficult and food and health the easiest subject. Among teacher-assigned grades (1 = lowest; 6 = highest), subject difficulties were largely comparable at the high end while the low end differed by more than one grade between the most and least difficult subjects. Some teacher-assigned grades were also independently assessed through external exams. These teacher-examiner pairs matched well at the low end but disagreed noticeably for high achievers. We conjecture three possible sources for such differences: the subjects themselves, the teachers, and the students.