Judge a return by the angle it leaves at, not by whether it went in

A deep neutral block that lands short of the baseline can hand the server the point more reliably than a return that misses.

Return percentage is the number everyone quotes and it flatters a shot that has already lost the point. Get it back. That is the coaching instruction, and it is right roughly half the time.

The reason is geometry. When a return leaves the racket, the two things that matter are how far the ball travels and at what angle it crosses the server's side of the court, because those two together set how much of the court the server has to defend on the next shot. A return hit deep and up the middle takes away angles and forces a neutral reply. The same ball hit at sixty percent of that depth, landing around the service line, hands the server a short ball and an open court. Both count as returns in play. One of them is a rally. The other is a slower way of losing.

There is a second effect that the percentage hides completely. A return with pace that stays low forces the server to hit up, and a server hitting up cannot attack, so the point resets to neutral even though the returner did not do anything spectacular. A high floating return that lands deep looks safe on the graphic and gives away the same advantage as the short one, because the server steps round it and hits the ball he was hoping for.

So the metric I want is the outgoing angle and the height at the net rather than the landing point alone. Ball tracking already captures all of it. It just is not what gets shown, because a percentage fits in a corner of the screen and a distribution does not.

The tactical consequence is that on second serves the block return is over-prescribed. Against a serve that sits up, taking a full swing and missing one in three is very often superior to blocking all three back short, because the two you make either win the point or leave you attacking, and the third costs a point you were likely to lose anyway. Coaches hate the arithmetic because the errors are visible and the slow surrenders are not.

I would rather watch a returner miss four in a set and dictate the other eight.

The safe return is the one that keeps you in the rally you have no way of winning.