Airbnb A/B Tests And Discovers That A Higher Button Position Is Better
Airbnb ran this wonderful experiment on one of their primary reservation buttons. The A/B test adjusted the position of the button, shifting it higher on all property pages - which was implemented once ended.
Highlighted UI Changes From This Leak
Higher Button Position
In variation B, we can see that the "Reserve" button's position was shifted above the pricing summary and below the calendar picker. I'm going to interpret that this was the primary change which most likely carried the positive impact (inferred by the final implementation decision).
We can make this guess because we have other similar A/B tests (with positive effects) that also made call to action buttons more visible by shifting them above the fold.
Underline Styling For Price Tool Tips
Furthermore, variation B also introduced a subtle styling adjustment. Notice how the price summary styles were changed from classic icon tool tips towards underlined text links. On this particular change, unfortunately I don't have any past patterns or data to share.
If I had to guess, perhaps the underlined links might have slightly encouraged more people to click on the links to clarify potential uncertainties - possibly a good thing? But again, this is a wild guess.