TL;DR — The billboard effect — guests discovering your hotel on Booking.com, then booking direct — is a verified phenomenon. Cornell's Center for Hospitality Research first documented it in 2011, with follow-up work in 2017 and 2021 showing the effect is real but shrinking. The lookup-to-book ratio has compressed from roughly 9-to-5 to closer to 7-to-3 as OTAs have improved their checkout flows. For most boutique and independent hotels, the math on "renting the billboard" stops working between 30% and 45% OTA mix — past that line, you are paying full commission on incremental bookings the billboard wasn't responsible for.
If you are an independent GM, you have heard this argument from your sales rep at Booking.com or Expedia: Yes, the commission is high, but think of all the guests who find you here and book direct. We're advertising for you. The argument is partially true. It is also the single most expensive way you could be buying advertising — if you don't run the math.
What the Billboard Effect Actually Is
The "billboard effect" is the observed behavior where a meaningful fraction of consumers who first encounter a hotel on an OTA listing then leave the OTA, navigate to the hotel's own website, and book direct. The hotel pays no commission on these bookings, but the OTA listing was the discovery mechanism.
The original Cornell research (Anderson, 2011) found that for every 1 booking on Expedia, 3 to 9 additional reservations were made through other channels (mostly direct). The 2017 follow-up (Anderson & Han) confirmed the effect persisted on Booking.com but with a tighter ratio. Kalibri Labs has produced annual reports on hotel channel mix that broadly support the same direction.
The phenomenon is real. The question is whether the current magnitude justifies the cost.
Why the Effect Has Compressed
Three structural changes have shrunk the billboard effect since the original Cornell paper:
1. OTA checkout has gotten radically better. In 2011, completing a Booking.com reservation took 7+ form fields and a credit card on a desktop computer. In 2026, it is one tap on Apple Pay. Friction was the entire reason the billboard effect existed; OTAs spent a decade removing it.
2. OTAs aggressively retain the user inside their app. Booking.com's mobile app retention is a deliberate moat — every push notification, every "Genius" reward, every saved card pushes the next stay back into the app rather than out to the property's website.
3. Branded paid search has become a tax. OTAs now bid on your hotel's name in Google. A guest who sees your property on BdC, types your name into Google with intent to book direct, and clicks the first paid result — often lands back on Booking.com. The billboard hands the guest off to itself.
The result: published 2024 data from Kalibri Labs and several independent CRO studies put the lookup-to-direct conversion ratio closer to 7-to-3 or 6-to-3 for independent properties — meaningfully lower than the 9-to-5 of the original Cornell paper.
The Math: When Does the Billboard Pay?
The cleanest framing is to ask: what does each incremental OTA booking actually cost me, accounting for the direct bookings the billboard generates?
Let: - C = OTA commission rate (assume 18% Preferred Partner) - B = billboard ratio (incremental direct bookings per OTA booking) - A = ADR
Net effective cost per combined (OTA + billboard direct) booking:
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Effective commission rate = C / (1 + B)
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| Billboard ratio (B) | Effective commission on the combined booking pair |
|---|---|
| 0 (no billboard effect) | 18.0% |
| 0.2 (20% incremental direct per OTA booking) | 15.0% |
| 0.5 | 12.0% |
| 1.0 (1:1 — every OTA booking generates 1 direct) | 9.0% |
| 2.0 (original Cornell ratios) | 6.0% |
In 2011, with 1.0–1.8 billboard ratios, OTA commission diluted to 6–9% effective — competitive with direct CPA. In 2026, with billboard ratios that have compressed to 0.2–0.5 for most boutiques, effective commission is 12–15% — still meaningfully above well-run direct CPA (8–11%).
The billboard effect did not disappear. It is just no longer subsidizing the OTA listing the way it used to.
When OTAs Actually Stop Paying
The decision rule is:
Keep OTA mix where billboard-diluted commission < your blended direct CPA.
For most independent boutiques running a respectable direct program, that breakpoint is around 30–45% OTA mix. Below 30%, the OTAs are still pulling in genuinely incremental discovery traffic and the billboard ratio is at its peak (because most of the people who would have booked direct already are). Above 45%, you are increasingly paying full commission on bookings the billboard wasn't responsible for.
The signal that you've crossed the line: your OTA bookings keep growing while your direct bookings stay flat or decline. That is not the billboard effect. That is OTA retention winning the rebooking, and it means each additional dollar of OTA mix is paying full freight.
How to Measure Your Property's Billboard Ratio
You cannot measure the billboard effect cleanly because the OTA never tells you which direct bookings came from a prior OTA discovery. But three proxies get you close:
- Branded search volume vs. OTA listing impressions. If you have access to Booking.com's analytics, compare monthly listing impressions to your Google Search Console branded query trend. A rising correlation suggests an active billboard.
- Geo-cohort analysis. Cross-reference OTA bookings by inbound market with direct bookings from the same market. If New York direct bookings track New York OTA exposure with a 2–4 week lag, the billboard is alive in that market.
- Listing-pause test. The cleanest experiment: pause Booking.com for 30 days in one of your softer demand windows. Measure direct booking decline. Most independents who have done this report a 5–18% direct booking drop — meaning the billboard ratio for that property was somewhere around 0.05–0.18, well below the Cornell averages.
The listing-pause test is the only one most operators actually trust, because it removes the confounders. It also terrifies people, which is why most don't run it.
What to Do About It
A practical four-step framework:
- Compute your effective commission with a reasonable billboard ratio assumption (0.3 is a defensible default for independents in 2026). Compare against your true direct CPA from the previous post.
- Run a listing-pause test on Booking.com or Expedia in a soft season, single property. 30 days. Measure direct decline.
- Tier your OTA mix. Many properties get most of the billboard benefit from the first OTA channel. The second and third produce mostly cannibalization. Most independents are over-distributed.
- Reinvest the recovered commission into the part of your funnel that doesn't run on someone else's billboard — your branded organic content, your booking engine, your virtual tour, your email program. That is the part of the asset that compounds.
The billboard effect deserves respect. It does not deserve unconditional surrender.
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