The range defined by either is often based on demographic factors, such as an increase or decrease in the relative numbers of younger or older students, with the aim of maintaining stable school populations. At this time, pupils are given more independence, moving to different classrooms for different subjects, which includes math, social studies, science, and language arts. Also, pupils are able to choose some of their class subjects (electives). Usually, starting in ninth or tenth grade, grades become part of a pupil's official transcript. In the U.S., children within this grade-range are sometimes referred to as "junior highers".