Why do I sometimes miss jump cut shots?
If the cue ball hits the object ball while it is airborne, the effective cut angle is larger. In these cases, you need to aim for a fuller hit to get the right cut angle. For more info, see:
The best way to see the effect is to hold a CB up against an OB and visualize a 1/2-ball hit (center-to-edge = CTE). Now slide the CB up on the OB, keeping the CB center in the CTE vertical plane. You will clearly see that different cut angles result, which you can verify by tapping the OB with the CB at different positions.
The jump over-cut effect can also effect non-straight follow shots, especially those with significant speed. For more info, see follow shot ball hop.
from Patrick Johnson:
No matter where the CB contacts the OB (on the equator or above it), the point where they make contact will be on the line between their centers (anything else is impossible), and the cut angle will be the line through their centers at that moment (ignoring throw). If you agree that an airborne CB travels farther before hitting the OB, then you must agree that the line through the CB/OB centers changes and therefore the cut angle changes.