Article: An angular shift error occurs when the sights are not properly aligned. You can usually determine if you are making a consistent angular error based on the placement of your bullet in the target.  If the bullet hits below the center of the target, the top of the front sight may have shifted below the tops of the back sight posts. If the bullet hits above the center of the target, the top of the front sight may have shifted above the tops of the back sight posts. If the bullet hits right of center, the front sight might be closer to the right side of the back sight. If the bullet hits left of center, the front sight might be closer to the left side of the back sight. Parallel shift errors occur when your sights are properly aligned, but your hand moves as you fire. Holding the pistol still results in the most accurate shot, but typically, parallel shift errors do not disrupt your aim as much as angular shift errors do. Parallel shift errors almost always result from your wrist either breaking up or breaking down, so the placement of your shot will usually be either just above center or just below it, respectively. Shift errors are not the only problems you might encounter. The placement of your bullet in the target could also indicate a handful of other problems.  If the bullet hits out of center and closer to your dominant side, you could be squeezing your thumb or using too much trigger finger. Similarly, if it falls to the other side of the center, you might be using too little trigger finger. If it falls to the lower right for right-handed shooters, or vice versa for left-handed shooters, you could be tightening your grip while pulling the trigger. If it falls to the lower left, you could be tightening your fingers or jerking the trigger. If the bullet lands to the upper right for right-handed shooters, or vice versa for left-handed shooters, you might be anticipating recoil in your shot. If it goes to the upper left, you might be anticipating recoil or lacking follow through.

What is a summary?
Identify angular shift errors. Pick out a parallel shift error. Spot grip and handling errors.