I have to agree with the size of the target factor.

When shooting at a live animal like a deer, anywhere in the 8" kill zone and you have a successful recovery. Beyond that most don't judge that their shot was 1" back and 1" too high from where they were aiming. Animal on the ground....good nuff.

Now switch to a stationary target with a defined bullseye and you now have the ability to clearly see that your arrow is 1" back and 1" too high.

Concentration certainly has something to do with it, but I would think that this is more than offset by the huge shot of adrenaline that is pumped into your system when you are drawing on a live animal.

Just my $0.02