Impressions, clicks, CTR — these metrics feel important but rarely tell you whether your advertising is actually driving business results. Here are the five numbers that matter.
1. Customer Acquisition Cost (CAC) by channel
Not blended CAC — channel-specific CAC. You need to know exactly what it costs to acquire a customer from Google versus Meta versus TikTok, including creative production costs.
2. Payback period
How many days until a customer’s lifetime value exceeds the cost to acquire them? This determines how aggressively you can scale.
3. Creative fatigue index
Track how quickly each creative variant loses effectiveness. This tells you when to refresh, not when the algorithm tells you.
4. Cross-channel attribution accuracy
What percentage of your conversions can you confidently attribute to a specific touchpoint? If this number is below 70%, your optimization decisions are based on incomplete data.
5. Decision reuse rate
How often are past campaign learnings being applied to new campaigns? A low reuse rate means your team is reinventing the wheel every quarter.