Sports Analytics Weekly by kubeia.io - 13/2026

Who Deserves Credit for Good Defending?

substack.com - Alex Marin Felices

This paper starts from a simple but still unresolved problem in football analytics: defending remains much harder to value than attacking. Offensive models have evolved quickly because passes, shots, and goals naturally create measurable events. Defensive contribution is different because many of the most important actions never appear directly in event logs. A defender may force a backward pass, remove a dangerous lane, delay an attack, or make a threatening option disappear entirely without recording a tackle or interception. That is why the authors build the whole paper around Paolo Maldini’s famous line: “If I have to make a tackle, then I have already made a mistake.”

The paper reviews how existing work still leaves important gaps. Metrics such as VAEP-style action valuation capture offensive actions well, while defensive methods often either work only at aggregate match level, focus only on explicit actions like tackles and interceptions, or evaluate team defense without distributing value to individuals. Even recent graph-based defensive models mostly study passing pressure qualitatively or restrict the analysis to pass prevention only.

To address this, the authors introduce DEFCON (DEFensive CONtribution evaluator), a framework designed to assign defensive credit in every game situation, not only when a defender touches the ball. The key idea is to estimate all available attacking options at a given moment, quantify how dangerous they are, estimate how likely they are to succeed, and then determine how much each defender is responsible for suppressing or allowing those options. Defensive value is then defined as the reduction in opponent scoring potential before and after an action. In practical terms, defenders are rewarded when they lower expected attacking value, penalized when they allow dangerous progression, and also credited when they successfully force opponents toward less threatening choices rather than simply stopping the action altogether.