How Event Data Gets Collected During A Live Match

The pass and shot counts on a match summary are produced by people watching the game and coding it as it happens. The process determines what the numbers can support.

Two systems capture different things

Event data records discrete actions with a type, a location and a timestamp. Tracking data records the positions of all players and the ball many times per second.

They answer different questions. Event data tells you what happened; tracking data tells you where everyone was while it happened, and neither substitutes for the other.

Most published statistics come from event data because it is cheaper to produce and easier to summarize. Tracking data mainly reaches the public through broadcast graphics.

The codebook is the real product

Operators work to a definitions document specifying exactly what counts as a tackle, a duel, a key pass or a clearance. That document constrains everything derived downstream.

Providers guard their codebooks because the definitions are the differentiator. Two feeds of the same match will disagree on tackle counts simply because they define contact differently.

When a provider revises a definition, the historical series breaks. Season-on-season comparisons through a definition change measure the change as much as the football.

Where human judgment enters

Coding a pass as a cross, or an action as a duel won, requires an operator to make a call in under a second while the match continues.

Providers manage this with quality control: a second operator reviews contested categories, and samples are audited against video after the match.

Judgment-heavy categories are consequently less reliable than mechanical ones. Pass completion is close to objective; pressure applied is a coded interpretation.

Latency and correction

Live feeds are transmitted within a second or two because they serve in-play products. That speed leaves no room for review before publication.

A post-match pass then corrects errors, and the corrected file is what analysts eventually receive. Live figures and final figures for the same match routinely differ.

Anyone quoting a statistic during a match is quoting the uncorrected version. The gap is usually small and is occasionally large enough to change a conclusion.

What the collection method makes impossible

Event data has no record of players not involved in the action, so questions about off-ball movement cannot be answered from it at all.

This is why so much public football analysis concerns shooting and passing. Those are the parts of the game the dominant data collection method happens to capture.

Tracking data closes that gap but is expensive and rarely shared. The shape of public knowledge about football follows the shape of what was cheap to record.

The phrase you hear in selection meetings is that a player is one-dimensional. It is said as a criticism. I have never fully understood why, given that the format is short enough that a team only needs a handful of dimensions in total and can distribute them across eleven bodies.

Consider the batter who can only hit down the ground and only against pace. He is useless in the middle overs against two spinners on a turning surface. He is also, in the right six deliveries, the most valuable player on the field, because the thing he does badly never comes up and the thing he does well comes up repeatedly.

The counter is obvious and it is about flexibility. If a wicket falls at the wrong moment, a specialist walks into a situation he cannot handle, and you have burned a slot. That is real. But it is a scheduling problem, not a talent problem, and scheduling problems have solutions that talent problems do not.

What actually happens is worse than either. Sides pick a squad full of players who are competent in every phase and outstanding in none, then wonder why they keep posting adequate totals and losing to somebody who had one man go berserk for four overs. Competence across the board is a way of guaranteeing you are never the reason a match turns.

I would rather carry two narrow players and accept that in a third of matches one of them is dead weight. The distribution of outcomes matters more than the average, because you do not get half a trophy for finishing consistently mid-table in a knockout competition.

There is a coaching dimension to this that gets ignored. Telling a specialist to broaden his game usually makes him worse at the thing he was picked for, because the technique that lets a player hit a length ball over long-on is not the technique that lets him work it into the leg side. They fight each other. He ends up in the middle, hitting neither shot with conviction, and within a season he is a squad player.

Leave him alone. Let him be strange.

The best selections I have watched were not the most complete cricketers on the list. They were the ones whose weakness the captain had a plan to hide.