A game model is a structured description of what a team should do in every phase of play: in possession, out of possession, transition to attack, and transition to defense. It goes beyond general style ("we press high") to specific player instructions by zone and situation ("when the ball enters zone X, the #8 closes within 1 second while the #6 drops to cover"). A complete game model is the prerequisite for data-driven tactical analysis — without it, you don't know what "success" means for a given team.
A well-defined game model specifies: (1) where the team defends (which zones, which press triggers); (2) how the team builds out (which zones route through, which players are ball-progressors vs. ball-retainers); (3) what success looks like in the final third (cross-heavy, combination play, direct); (4) transition behaviors (immediate press on loss, or drop to shape?). Success metrics differ by coach — a model that defines "getting wide" as success requires different data than one that defines "entries into the box."
Coaches can't articulate their game model verbally but can instantly identify what they want from video. Asking "describe your model" produces platitudes. Showing clips and asking "is this what you want?" produces precise descriptions.