A good point is "return business". Any business which has return customers must be doing something satisfactory.

A REALLY good question for any referee clients is:

"Would you book another hunt/safari with this outfitter/PH/Concession? If not, why not?"

Because I can say, I would give an OK reference for some outfitters or PHs, but won't probably rebook with them again.

An example. I hunted with one very competent guy. Serious dangerous game experience, a CV which included some of the best names in the outfitting business. He conducted the safari given the circumstances well. It was on balance successful. But I wouldn't rebook with him because he was immature. And he constantly talked about his "rich clients" and the inference was "it was a pity I didn't have more money and wasn't richer" and "a lear jet at the strip so we could fly to the coast for a day off".

A small thing, which one just shrugs off during a hunt, but no intention to book with the guy again.

Very instructive question if answered honestly by the referee.