A single possession is not a uniform event — it comprises a sequence of micro-objectives, each with different success criteria and different analytical requirements. Three phases: (1) Build-up — overcoming the first line of pressure, getting the ball into the opponent's half, avoiding dangerous turnovers near your own goal; (2) Progression — moving past the organized defensive block into more advanced zones; (3) Finishing — creating and converting a scoring opportunity. Most analytics research focuses disproportionately on the finishing phase, leaving build-up and progression analytically underexplored.
Classify every possession moment into its current phase before running any analysis. Build-up begins when the team gains possession in their own half; progression begins when the ball crosses the halfway line with the opponent's first defensive line behind it; finishing begins when the ball enters the final third with a direct path to goal. Phases are not strictly sequential — direct play skips progression; a turnover resets; a clearance to halfway restarts. The correct analytical question always depends on which phase you're analyzing.
Football analytics disproportionately focuses on the finishing phase (xG, shot quality, conversion rates) while the majority of possession breakdowns occur in the build-up and progression phases. A team that never reaches the finishing phase has no use for shot quality analysis. The bottleneck is almost always progression (moving past the organized defensive block), not finishing — but progression analytics is dramatically underinvested.