From tracking data to ecologically grounded tactical indicators: a conceptual validation procedure for team invasion sports.

Tracking systems and AI-assisted models now describe team invasion sports in considerable detail. They estimate distance, speed, pitch control, passing probability, pressure, expected possession value, and many other position-derived variables. The difficulty is not the measurement itself. It is the step that follows, when a spatial or predictive output is written as if it already carried tactical meaning. A passing lane can be geometrically open and still be unusable for the current ball-carrier; a defender can be close without restricting the relevant exit; an action-value model can predict a useful action without showing that the action was locally available in the episode. This article defines E-PART as a five-step conceptual validation procedure for judging whether a candidate tracking-derived variable may legitimately be reported as an ecologically grounded tactical indicator. E-PART stands for Ecological constraints, Positional relationships, Action-opportunity specification, Representative task boundaries, and Tactical emergence. The procedure starts with a neutral position-derived variable and examines the performer-task-environment relation that the variable is asked to represent. It then leads to one of four reporting decisions: report the variable as a bounded tactical indicator, qualify the scope of the claim, downgrade the output to spatial or predictive description, or reject the tactical interpretation. The paper's central claim is narrow: tracking-derived variables become tactical indicators only when the inferential chain from coordinates to action opportunity to tactical consequence is stated, bounded, and open to empirical testing. The contribution is therefore procedural. E-PART makes the move from position-derived measurement to tactical interpretation visible, criticizable, and reportable.