The paper by the Centre for European Economic Research (ZEW) (PDF 725 KB) suggests that OTAs make the ranking of their recommended search results dependent on factors that are relevant for the OTA to maximize its profit, but arguably not to maximize the match value of customers.

Interestingly, for Expedia the paper finds a larger effect of lower prices on competing channels on the ranking than for

This could indicate that is more careful because it committed to competition authorities in Europe that “’s ranking algorithm will not take into account directly whether an accommodation refuses to enter into or does not comply with Price Parity.

Read also: A quarter of hotels more expensive on OTAs