The goal is 15% close of opportunity here, which is tough considering the number of Honda dealers near me (we do it anyways). I've always preached contact to opportunity (actual interaction), appointment to contact, show to appointment, and sold to show.
Also, a HUGE measuring point is I compare the reps to each other on their p/c gross. A large difference in p/c could mean the customer is not being brought in cleanly, and with the right expectations. If someone is too low it may mean they are not approaching customers right and there can be improvement on the appointment and show percentages.