Review invitation email vs SMS: what wins by UK sector

The blunt headline: neither channel wins everywhere

Across the whole 2024–2025 UK dataset, SMS invitations converted at 21.4% and email invitations at 17.9%. That headline hides more than it shows. Once we split by sector, the picture inverts: email wins in legal, accounting and hospitality; SMS wins by a wide margin in trades and retail.

The reason is context. SMS wins when the customer's original transaction was completed on a phone (job booked by phone, receipt SMS-ed, appointment SMS-confirmed). Email wins when the transaction produced a paper or PDF trail (invoice emailed, booking confirmation emailed, statement mailed).

In the review invitation email vs SMS decision, the correct question is not 'which channel do we prefer' but 'which channel already carries the customer's receipt today'. Follow that channel.

A secondary factor is customer age. UK customers over 60 respond to email at almost 2× the rate they respond to SMS; customers under 30 respond to SMS at 1.7× the rate of email. Mixed-demographic operators (hospitality, retail) benefit from a channel-of-choice option in the invitation.

Sector-by-sector response rates and cost per response

The table below reports median 2024–2025 UK response rates per channel per sector, plus the cost per successful review at April 2026 UK unit prices. 'Cost per response' is the fully-loaded cost of the invitation channel divided by the reviews it produced, not the pro-forma per-message price.

The 'both' verdict for dental and private GP is the interesting case. Neither channel wins outright, and the small lift from running both together (typically +4 percentage points on total response) more than pays for the extra channel because the underlying appointment revenue is high.

The 'winner' column is a shortcut; the fuller answer depends on your invitation volume. Below roughly 200 invitations per month the channel choice does not swing profitability meaningfully; above 1,000 invitations per month it becomes a five-figure decision annually.

When to run both channels — and how

Running both channels together only makes sense in sectors where neither wins decisively (dental, private GP, some hospitality segments), and only with a specific sequence. Simultaneous send always underperforms sequential send.

The one common mistake we see: sending both channels within an hour of the transaction. It reads as pressuring and unsubscribe rates spike. The 48-hour gap is what makes the second channel read as a courtesy nudge rather than a marketing sequence.

For operators that already have a two-touch marketing sequence configured, add the review invitation as a distinct workflow with its own consent basis under UK GDPR. Do not append it to a marketing sequence — the legal basis and the deliverability profile are different.

1. 1Send the primary channel at the transaction point (email for hospitality, SMS for trades, either for dental).
2. 2Wait 48 hours for a response.
3. 3If no response, send the secondary channel with a slightly different wording — reference the previous message so it does not read as duplication.
4. 4Never send a third invitation. It converts poorly and materially raises unsubscribe and spam-flag rates.

The channel-of-choice pattern (recommended for mixed demographics)

For operators with a wide age range (restaurants, retail, fitness), the highest-performing pattern in 2024–2025 was letting the customer pick the channel at the point of the transaction. This is a small UX change with a disproportionate response lift.

At bill-close, ticket-sale or checkout, offer 'Would you like your receipt by email, SMS or WhatsApp?' If the customer picks a channel, use that same channel for the review invitation 60 minutes later. Response rates in our 2024 mixed-demographic subset rose from 16% (SMS-only) and 18% (email-only) to 26% (channel-of-choice), on the same underlying customer base.

The mechanism is simple: you are asking on the customer's own terms. Consent is stronger, deliverability is higher (because the address was just used successfully), and the invitation lands in whichever inbox they already opened for the receipt.

WhatsApp is emerging as a strong third option in UK hospitality and trades, particularly for younger customers and international visitors. Response rates in our 2025 partial sample are close to SMS performance at a lower per-message cost, but coverage is still uneven — treat as an experiment before rolling out.

“We stopped asking 'email or SMS?' internally and started asking 'what did the customer just use to pay?' The response rate answered itself.”

Summary: the decision in one paragraph

For most UK operators, the review invitation email vs SMS decision is answered by the receipt channel: use whichever channel already carried the customer's transaction receipt. In sectors where no dominant receipt channel exists, use channel-of-choice at the point of sale. Simultaneous multi-channel sends underperform; a 48-hour delayed secondary channel outperforms.

The one universal move: personalise every invitation with the staff name, the job or product, and the platform. The channel choice matters, but personalisation carries roughly 3× the response lift of channel choice, and it works in either channel.

Revisit the decision annually. The gap between SMS and email costs is not stable, and WhatsApp is moving fast enough in the UK market that the correct 2027 answer may look different from the correct 2026 one.