[quote=sbates]well, I don't think they are additive. How do you interpret what I copied and pasted directly???[/quote] Out of the %10 that don't make the grade %60 do so for one reason and %40 for the other reason. %90 is optimistic but I'm just regurgitating what I read 15 years ago when I was really interested in any information about dogs I could find. As such my memory could be faulty and it may be %80 or %70 but still that would be a rate that is highly consistent with predictions. You didn't acknowledge my point about narcotic detection dogs which is related to explosive detection dogs. All you need for that is a dog with extreme ball drive. Fairly easy to make this assessment in about 3 minutes with a young dog.