Cross Eye Dominance Test

If a shooter is consistently shooting to one side or the other of their point of aim, they may be cross-eye dominant.

This means that they are right handed and left "eyed" or left handed and right eyed. This is not as uncommon a condition as most people think.

According to Wikipedia about 1/3 of the population is left eye dominant. Handedness doesn't determine "eyedness." Dominance is a matter of visual preference, environment and circumstance.

To determine if this is the case, start by having the shooter form a window with their hands with their arms fully extended.
Have the shooter gaze through the window at a distant object.

Tell them to bring their hands back toward their face, but not lose focus on the distant object.

Apart from being kind of creepy, the picture to the right shows that the window will end up over the dominant eye.