From a squad list to a decision about Tuesday

Developability is how much value would be created by closing the one limiting factor holding a player's price down. It is not a measure of how good he is.

Step 1. The problem

A club has a squad, a training week that is already full, and a development budget measured in hours rather than money. Somebody decides where those hours go. Usually that decision is made in a corridor.

The instrument exists to make it a decision that can be written down, argued with, and checked afterwards.

Step 2. Screen

Before anything is scored, four questions are answered yes or no. Each is answered against stated evidence, not against an impression.

Flaw type. Is the limiting factor the kind of thing that actually changes? A weakness bound by height or maturation is not a development project, however visible it is.

Value threshold. Would closing it change what this player is worth, or where he is selected? If nothing downstream moves, the work is not worth the hours.

Runway. Is there enough developmental and calendar time to move it? Age against positional peak, contract horizon, and enough season left to see it through.

Observability. Can the change be seen well enough to measure? One training measure and one competition measure, both nameable before the work starts, both capturable from video the club already has.

Any single no and the player is not scored.

That is deliberate and it is the part most worth understanding. A model that always returns a number has never told a buyer no. When a player fails a gate, what comes back is not a low score. It is a reason, and a routing answer.

Worked example: a player who is not scored

A 29 year old wide forward. A genuinely good crosser, better than most players at his level. His limiting factor is beating a defender one against one, which is why he gets far fewer chances to cross than his delivery deserves.

He clears the first two questions. The weakness is the kind of thing that changes, and closing it would change what he is worth.

He fails the third. He is past positional peak, the weakness has been coached around for years rather than closed, and there is not enough developmental runway left for the work to pay back inside his contract. The fourth question is never run.

Output: no index, no value figure, no engagement proposed. The answer is to design the role around the limitation rather than spend a season trying to close it. Get him the ball in positions where he is already facing the right way.

That is worth more to the club than a mid-ranking score would have been, because a mid-ranking score would have bought twelve weeks of work against something that was never going to move.

Step 3. Score

Only players who clear all four questions are scored. Four factors, each between 0 and 1.

Leverage. How much priced value the weakness is currently suppressing.

Coachability. How tractable this kind of weakness is to methods that exist.

Transfer. Whether a trained change will show up in competition rather than only in training.

Runway. How much developmental room is left.

The four combine into a Developability Index between 0 and 100. The breakdown is always shown beside it, because an index of 65 held down by borderline transfer is a very different project from an index of 65 with everything mid.

Interference risk is reported beside the number and never inside it. Retooling a technique under load can disturb the strength you were trying to release. That risk is a flag a coach can see, not something averaged away into a score.

Worked example: a player who is scored

The 21 year old wide forward from the home page. Elite in the carry, one footed in his end product.

Developability Index: 76 out of 100. Interference risk: moderate.

Step 4. Rank

An index tells a coach whether a project is worth doing. It does not tell a sporting director where to put a training week.

That is what Return per hour is for. It is the value a project is expected to create, divided by the hours of squad contact time it takes.

Hours rather than money, because money varies by club and hours do not. A club with budget still cannot add hours to a training week. Fixtures, availability and session length are fixed. Hours are the thing that is actually rationed, so hours are what the ranking is built on.

The denominator is capped, and the cap is counted in thirty minute blocks.

One block is thirty minutes. A player gets between one and three blocks a week. Thirty minutes is the floor, because less than that is not an intervention. Ninety minutes is the ceiling, because more hours do not buy more skill indefinitely. Learning consolidates between sessions rather than during them, and the training week is already shared with everything else.

Blocks are either added to the week or transferred from time the club already runs. Added blocks are capped at the lesser of two blocks, or ten per cent of the club's combined weekly training and competition load, rounded down to a whole block. Anything beyond that has to come out of time that already exists.

So a club training six hours a week and playing one game has a seven and a half hour baseline. Ten per cent of that is forty five minutes, which rounds down to one added block. A second or third block, if they are used, are transferred rather than added.

Over a twelve week engagement that is a maximum of eighteen hours and a minimum of six.

Hours beyond the cap do not count toward projected value, so nobody raises a ranking by proposing to throw a training week at one player.

A cheap small project can outrank an expensive large one. That is the comparison a director with a fixed training week is actually making, and the previous version of this instrument could not produce it.

Step 5. Act

The score names the constraint. Something then has to happen on a training pitch.

That work is designed using Intention-Led Practice Design, which is our own practice design framework. It runs on two decisions the coach makes deliberately rather than by default: how much of the solution is named in advance, and whose conditions get constrained.

What the club receives is not twelve weeks of an outside coach. It is a coach on the staff who now sees the problem differently, and a written record of what was designed, what came back, and what changed in response.

That record is the part that survives someone leaving.

Step 6. Re-score

Developability is a state, not a trait. It changes when the weakness closes, when the runway shortens, or when a step up in level exposes something new.

The instrument is run again at the end of the block. The movement in the number, against a prediction that was written down and signed before the work started, is the evidence. Not a testimonial afterwards.

Completed cases also correct the instrument. If a factor routinely overshoots, its anchors get adjusted. If players who cleared the observability question routinely turn out to be unmeasurable, that question was set too loosely.