Could you not skip those with prescriptions to the stimulants (Adderall, etc) to reduce sample space? Then your method would work well in theory. Of course, in

Could you not skip those with prescriptions to the stimulants (Adderall, etc) to reduce sample space? Then your method would work well in theory. Of course, in practice, who wants to take a drug test? Certainly not before an exam! It would be chaotic