The ways by which students are assigned to tracks differs both between and within schools. Today, it is less common for schools to rigidly track students in all subjects. Administrators and teachers in a given school may purposefully avoid using the term “tracking” to describe the organization of their school’s curriculum. Yet, schools maintain a variety of policies that sort students into different programs of study including: test scores and grade requirements, pre- and co-requisite requirements, and teacher recommendations. Schools also use over-arching programs of study such as “college prep” as a guidance technique to track students. Non-academic factors such as schedule conflicts can limit students from taking courses of varying level as well. Thus, while most systems allow for some amount of student and parent choice, this choice is constrained by course taking requirements and guidance policies. Within the context of this system, researchers disagree over the extent to which highly involved parents intervene to give their own student a course taking advantage.