Electronic word of mouth (eWOM) is of recent and considerable importance in tourism, particularly because of the intangible nature of this industry. Users' online reviews are a source of information for other consumers, who take them into account before making a reservation at a lodging property. The aim of this study is to establish whether or not the anonymity of the reviews on TripAdvisor alters hotel rankings by comparing them with verified users' reviews on Booking.com. Moreover, the study analyzes whether or not the differences in the rating scales of both websites favor some hotels over others. Big data is used in this study, with more than 40,000 hotels on Booking.com and 70,000 on TripAdvisor in 447 cities around the world, and compares the rankings of about 20,000 hotels matched on both websites. Our findings suggest that the behavior of both rankings is similar and the lack of veracity on TripAdvisor due to the anonymity in the user's verification system is baseless. In addition, some differences are found depending on the hotel category and region, due mainly to the unique rating scale on Booking.com (from 2.5 to 10), as compared to the rating scale on TripAdvisor (from 1 to 5).