Expertise, experience, overall intelligence, personal gain bias, how much would they bet (assuming equal bankrolls and equal gambling proclivities), are they the type who will only offer an opinion they are sure of. Those last two are rarely considered.
If you are getting conflicting advice from two experts is there any way to choose? I think so. At least theoretically. I think five factors should be weighed if you know them. The obvious one is the amount of knowledge they have about the subject they are disagreeing about. But the four other factors could often swing your decision to the other person. One is their overall intelligence. By which I mean their susceptibility to logical errors, similar but not exactly the same as IQ. This is important because knowing all the facts is of no help if you are apt to screw up when deducing conclusions from those facts. Then there is bias. If one of the experts benefits from his stance being true (or is harmed if the other stance is true) while the other expert has no such concerns, lean away from the person who might be consciously or subconsciously recommending the side that helps him. This concept becomes even stronger if the expert recommends AGAINST the side that is better for him personally (eg the surgeon who recommends against surgery.)
The last two are rarely considered. When I said “how much would they bet” I of course meant “assuming their personal financial situation and attitude towards gambling are similar”. And I am using gambling as a stand in for the words “which one is more certain that they are correct”. Meanwhile if both experts are both competent and otherwise anywhere near equal, my fifth factor trumps them all. If one of those experts is known to keep his mouth shut unless he is almost absolutely sure he is right while the other one isn’t, go with the first one Period.
Some considerations about experts having a financial stake in the correctness of his/her opinions.
1. Some people are more risk adverse than others.
2. A million dollars to one expert could be “walking-around” money while another person losing that much money could result in bankruptcy or other hardships.
3. The answer who is absolutely right or wrong might not be known and widely accepted for many years.
4. In theory, being wrong would damage a person s reputation, prestige, ability to get speaking engagements, etc., but quoting Bill O’Reilly,
“We live in an age where truth doesn’t really matter anymore.”