How to actually measure SMS ROI
Attribution windows, incrementality, and the metrics that survive a finance review.
If you can’t measure it, you can’t defend it. Here’s how to put a credible number on what SMS earns - one that survives a finance review.
Pick an attribution window
Decide how long after a text a purchase still counts - often 24 hours to 7 days, depending on your buying cycle. Be consistent, and document it.
First- vs last-touch
Last-touch credits the final nudge; first-touch credits what started the journey. Look at both - they tell different, useful stories about how SMS contributes.
Prove incrementality
The strongest case is a holdout: keep a small, random group out of a send and compare. The revenue difference is the lift SMS actually caused, not just correlated with.
Report ROI honestly
Divide attributed revenue by the all-in cost - messages, platform, and the time to run it. A number you can stand behind beats a flashy one you can’t.
- Window: fixed and documented.
- Model: show first- and last-touch.
- Lift: prove it with a holdout.
- ROI: all-in cost, honestly.
Do this and SMS stops being a line item people question - and starts being one they fund.