The amount of work performed by the student must be rigorous enough for the number of credits the student will earn for this Directed Study or Independent Research. For accreditation purposes it should meet the Credit Guidelines set by the Federal Government, see below.
Federal Government definition of a Credit Hour:
"… an amount of work represented in intended learning outcomes and verified evidence of student achievement that is an institutional established equivalence that reasonably approximates not less than-
(1) One hour of classroom or direct faculty instruction and a minimum of two hours of class student work each week for approximately fifteen weeks for one semester or trimester hour of credit, or ten to twelve weeks for one quarter hour of credit, or the equivalent amount of work over a different amount of time.
(2) At least an equivalent amount of work as required in paragraph (1) of this definition for other academic activities as established by the institution including laboratory work, internships, practica, studio work, and other academic work leading to the award of credit hours."
In the case of a Directed study or Independent research the student should be doing most of the work under the guidance of a faculty member. For each credit awarded in the directed study/independent research, this translates to about 45 hours of work.