When Certification Backfires: Negative Spillovers on Noncertified Offerings in Airbnb Plus
Certification can hurt uncertified offerings through contrast: Airbnb Plus made non-certified listings look worse.
Summary
The study compares Los Angeles, where Airbnb Plus launched in February 2018, with the similar city of San Diego, where it launched in the autumn, using detailed booking and revenue data. Plus listings were only a little over 3% of supply in Los Angeles, yet non-certified listings earned less than they would have without the programme. The explicit verified label created a contrast, so guests seeing certified and non-certified homes side by side saw the latter as uncertain or risky even when their actual quality was unchanged, and some guests left the platform for hotels instead of trading down to cheaper listings. The harm was uneven: listings with high ratings or many reviews, little direct competition from Plus homes, or few hotel substitutes lost less. Certification programmes therefore carry platform-wide costs, and benefits to premium participants can alienate the wider base that powers the marketplace.
Editor's opinion
A quality badge does not only lift the badged: it makes everything without the badge look riskier, and some customers leave the platform altogether. Platforms should count the cost to the unbadged majority when they launch a premium tier, and sellers outside the tier should compensate with strong ratings and reviews.
Key concepts
certification · negative spillover · contrast · Airbnb