The test
Om Mushrooms (ommushrooms.com) had been offering shipping protection at checkout only. For three weeks the offer appeared in the cart instead, as a switch the shopper could turn on before they started checking out.
What moved
Orders with protection added
20.7% to 57.6%
A large, clean effect, and the number we are most confident in. It comes from where the offer sits, not from how it is worded or priced.
Store conversion rate
2.07% to 2.26%
A relative lift of 9.06%, or 0.19 percentage points. This is an early result: one store, three weeks, 80% confidence. Treat it as a direction, not a forecast.
Why conversion would move at all
Protection is a risk-reversal moment. A shopper who sees their package is protected has one less reason to hesitate, so more of them finish checking out.
At checkout the shopper has already decided. In the cart they are still deciding, and that is where a reason to feel safe can change the outcome. The attach rate shows shoppers want the offer when they see it early; the conversion figure suggests that seeing it helps them commit.
What we are still waiting on
The conversion lift needs to reach 95% confidence and repeat at a second store before we state it without a caveat. Until then, every place it appears on this site says so. The attach rate stands on its own.