Normalize, Reconcile, Document
Harmonize product hierarchies, currencies, fiscal calendars, and channel tags before analysis begins. Reconcile totals across sources, flagging acceptable tolerances and investigating persistent gaps. Keep a living data dictionary and detailed revision history so updates are transparent. When new SKUs or routes appear, fold them into definitions deliberately rather than ad hoc. This discipline protects comparability across quarters, enabling leaders to trust trendlines and anchor ambitious bets to numbers that actually align.