That is all I use while bait fishing for trout!
I have no study to back me up but I saw a huge decrease in the number of gut hooked fish. Also I found that I lost larger fish and gut hooked fish more often using a small circle hook. I use a 1 not instead of a 6 or 8. Also the type of rod makes a difference in the hookup and play in the fish. I like a 7 foot ultralight 4-6 pound test. when you detect a bite a nice long sweeping motion also will increase the hookup ratio. It takes some getting used to but worth it. also the way you drift makes a difference. Always try to stand behind the hole not next to it. THe best hookup is when the fish is in facing away from you because of the way a circle hook works. If you do end up next to the hole you are drifting always make your sweeping hookup downstream and As I said multiple times Sweeping not setting!
Good luck!