Block totals cannot tell you who defends the break

A centre can lead a league in blocks and still be the reason his team concedes easy baskets in the open floor.

Blocks are the most misleading counting stat in basketball and they are misleading in a specific direction. They reward a defender for being present at the moment of a shot. They say nothing about whether he was present at the moment the shot became inevitable.

In the half court, presence is mostly automatic. The centre is standing in his own paint, the action comes to him, and shot blocking is a skill applied to opportunities that arrive on their own. In transition, presence is the entire skill and there are no automatic opportunities. He either turned at the release and ran, or he did not, and if he did not then the layup happens with him three strides behind and no block is recorded, no shot is contested, and his blocks per game is unaffected.

Which means a big man can produce an outstanding rim protection profile and still be a bad rim protector, because the shots he does not affect are invisible to the metric that describes him. Opponent field goal percentage at the rim is better and inherits some of the same blindness, since it only counts attempts near him, and the attempts he was too slow to reach are attributed to whichever unfortunate guard ended up under the basket instead.

The number I would build instead is arrival based. For every opponent shot attempt inside the restricted area, record where the centre was when the possession started and whether he reached a defined defensive position before the shot went up. Then split it: half court arrivals, transition arrivals. Two entirely different columns for two entirely different abilities.

I suspect that split would reorder a lot of reputations, and I suspect the reordering would follow age. Older centres protect the rim beautifully in the half court and stop being there in transition, sometimes years before anyone says so out loud, because the block totals stay respectable and everybody reads the block totals.

Teams paying for rim protection are frequently buying the half court half and quietly not receiving the other one.

The block is a photograph. Rim protection is a journey, and the camera only ever shows up at the end of it.