PowerReviews, a review platform, reports that 70% of its clients’ reviews come from emails sent after purchase Reported (vendor data). So the review request is not a small flow. It’s the machine that writes most of your social proof, and its settings shape the result.

Asking changes who answers

• It brings back the middle. In Brandes, Godes and Mayzlin’s field experiment, plain request emails with no incentive made incoming reviews less extreme Published.
• It raises volume and can crowd out the rest. When hotels joined TripAdvisor’s review solicitation program, review volume rose 34.3% and ratings rose 0.151 stars, but reviews got 16.9% shorter and unprompted reviews fell 15.5% (Baojun Gao and colleagues, 2025) Published. Solicited reviews partly replace organic ones rather than adding to them.
• Money buys count; norms buy length. In a field experiment with a large online clothing retailer in China, Gordon Burtch and colleagues found a financial incentive produced more reviews but not longer ones. Telling customers how many peers had written reviews produced longer ones. The two together did best Published.

So: ask everyone, once, with one reminder; use a true social-norm line (“2,314 customers have reviewed this”); and expect a reward to buy more short reviews, not better ones.

Time it to use

A review is only useful if the writer has used the product. Asks timed to fulfillment arrive before the product and produce reviews about the courier, or nothing. The right trigger is delivery plus the time to form a view: days for a T-shirt, weeks for skincare or supplements.

Say a brand ships 3,000 orders a month, delivery takes four days, and most customers have used the product enough to judge it about two weeks after it arrives. Say 8% of customers who have used it answer an ask, 3% of those who haven’t still reply with something about delivery, and interest halves every 30 days after the right moment. The tool shows what the send day does.

With those defaults, an ask on day 7 produces about 51 product reviews a month plus 71 about delivery, so 58% of what comes in says nothing about the product. Moving it to day 18 produces about 240 product reviews a month, and a new product selling 150 a month reaches five reviews in about two weeks instead of two months Derived. Your own rates will differ; the shape usually won’t.

Trigger the ask from delivery plus use, never from the shipping label.

If results take a month to show, as with skincare, send a first-impressions ask at two weeks and a results ask at five, labeled on the review. Text only customers who agreed to texts. Appendix B has both versions.

What you may not do

• No gating. Don’t ask only the customers you expect to be happy, or route unhappy ones to support instead of the review form. The FTC’s 2022 guidance: “Don’t ask for reviews only from people you think will leave positive ones” Published.
• No rewards tied to sentiment. Since October 21, 2024, the FTC’s rule bans giving anything of value conditioned, expressly or by implication, on a review expressing a particular sentiment Published. “Leave a five-star review for 15% off” is exactly that.
• Disclose any reward on the review itself. A free product or a discount for any honest review is a material connection under the FTC’s Endorsement Guides, and the UK requires incentivized reviews to say so Published.
• Check each platform’s own rules. Google Maps bans incentives for any review and bans selectively asking happy customers Reported. Marketplaces set their own rules too.

Do this

• Change your review flow’s trigger from fulfilled to delivered, set the delay by category with the tool, and remove any star-rating filter or sentiment-linked reward from the flow this week.