Trend Visualization is the reporting interface that makes Catalyst's measurement data actionable. Rather than static snapshots, it shows how key metrics are moving over time: advance booking compliance trending upward, preferred supplier adoption by quarter, cost avoidance accumulating month over month. Travel managers can see at a glance whether their program is improving and which tactics are driving the results. The visualization layer supports drill-downs by tactic, group, and time period. This is what travel managers show leadership when asked 'is the program improving?' — clear directional indicators with defensible data behind them.