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Defensive Dynamics Impact (DDI)

Player EvaluationLevel 4 β€” Expert

Prerequisites

Pitch-Control-Adjusted Recovery

What It Is

DDI = Pre-Recovery PC minus Pre-Recovery β€” the marginal contribution of defensive spatial positioning above and beyond the situation itself. Teams with high DDI win the ball back more often through off-ball structure rather than direct pressing. Bielsa-era Leeds had DDI values 4x higher than their successors, capturing the coaching philosophy in a single metric.

Correct Execution

Compute both models per team per match. DDI = average(Pre-Recovery PC - Pre-Recovery). Positive = the team's positioning consistently adds recovery probability beyond what the baseline situation predicts.

Diagnostic Tree

Edges

πŸ’Ž Elite-Only Behavior

DDI Captures Coaching Philosophy β€” Same Players, 4x Different DDI Under Different Managers

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Bielsa-era Leeds had DDI values 4x higher than their successors with the same core players. DDI changed because coaching changed, not players. DDI measures the coach's defensive system, not individual quality.

What most people do
Attribute defensive improvements to player recruitment. Use pressing metrics that measure individual actions.
What the best do
Use DDI to isolate coaching contribution. Compare before/after manager changes. Use DDI in manager recruitment.
Why it's an edge: Manager evaluation based on results conflates squad quality with coaching quality. DDI provides a coaching-specific defensive metric.
How to exploit: Build a manager DDI database. A manager with consistently high DDI across different squads is a genuine defensive tactician.
Ricardo Furbino, StatsBomb Conference, 2022-10-05
πŸ”‘ Hidden Causal Lever

Defensive Value Is 3x Harder to Measure Than Attacking Value β€” And Clubs Overpay for Attack as a Result

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Defensive contributions are structurally harder to quantify because great defense often means nothing happens β€” no shot, no chance, no event to record. A center-back who positions perfectly so the opposition never attempts the through ball creates enormous value that generates zero data points. Attacking contributions (goals, assists, chances created) are directly observable and quantifiable. This measurement asymmetry causes a systematic market pricing error: clubs overpay for attackers (whose value is fully captured in data) and underpay for defenders (whose value is mostly invisible).

What most people do
Evaluate defenders using event-based metrics (tackles, interceptions, clearances) which only capture reactive defending β€” the things that happen AFTER the positioning has already failed.
What the best do
Use tracking data to measure proactive defensive value: how much opposing xT was suppressed by defender positioning alone (no tackle or interception needed)? This requires 360 data and spatial threat models but captures the majority of defensive value that event data misses.
Why it's an edge: The most valuable defenders are the ones whose metrics look least impressive because they prevent events from happening. A CB who makes 0 tackles per game because nobody dribbles at them is likely better positioned than a CB who makes 4 tackles per game.
How to exploit: Build "threat suppressed" metrics from 360/tracking data. Identify defenders whose presence reduces opposing xT more than their event-based metrics suggest. These players are systematically underpriced.
Gregory Everett, StatsBomb Conference, 2022-10-03. TAx (Threat Above Expected) as a measure of positioning quality.

Sources

  • Ricardo Furbino, Federal University of Minas Gerais, StatsBomb Conference 2022, YouTube, 2022-10-05