Turn Students Into Investments

Ryan Christianson has an idea about how to determine teacher's salaries that he admits is "kind of crazy." He writes:

What if teachers were paid based on the future income their students make. For example, student A grows up to make 100k a year. We look at the records and find the 20 teachers that taught student A and compensate them based on that. Compensation could be based on number of months spent with student.

That way the students would turn into "investments" for the teachers.