Metrics Glossary
Use these definitions consistently across reports and SOPs.
Commerce Metrics
| Metric |
Definition |
Notes |
| Sessions |
Visits to the online store |
A single user can create multiple sessions |
| Online store visitors |
Unique visitors where available |
Useful for reach, not a substitute for sessions |
| Add-to-cart rate |
Sessions with cart additions divided by sessions |
Measures product and offer pull |
| Reached-checkout rate |
Sessions that reached checkout divided by sessions |
Measures cart and checkout intent |
| Conversion rate |
Orders divided by sessions |
Main purchase completion metric |
| Average order value |
Sales divided by orders |
Watch for discount and bundle effects |
| Revenue per session |
Sales divided by sessions |
Useful for comparing traffic quality |
| Bounce rate |
Sessions with no meaningful engagement |
Diagnose by channel and landing page |
Web Vitals
| Metric |
What It Measures |
Good |
| LCP |
Largest visible content load |
2500 ms or less |
| INP |
Interaction responsiveness |
200 ms or less |
| CLS |
Visual layout stability |
0.10 or less |
| FCP |
First visible content |
1800 ms or less |
| TTFB |
Server response start |
800 ms or less |
Interpretation Rules
- Always compare metrics against the same date range when possible.
- Separate traffic mix issues from page conversion issues.
- Call out sale periods, campaign changes, stock issues, outages, and test overlap.
- Treat small samples as directional.
- Use revenue per session when CVR and AOV move in different directions.