ABSTRACT
This study extends the literature on big data applied to tourism by validating the significance of point-of-sale (POS) electronic transactions, which have received little attention within tourism literature, as a reliable and effective alternative to surveys on guests stays at tourist accommodation establishments. Compared with official statistics on occupancy of tourist accommodation establishments, data on POS transactions tend to exhibit greater volatility and a less adverse year-on-year variation during the COVID-19 pandemic in Portugal. Still, both data sources reveal the same underlying trend. POS electronic payments, namely, at lodging establishments, deliver timely data for most municipalities in Portugal, filling in significant data gaps in many low-density areas, where statistical confidentiality is imposed in tourism indicators. This supports POS data's effectiveness to analyse regional inequalities at the municipal level, allowing to gain a clearer understanding of the impacts of COVID-19 in domestic tourism. © The Author(s) 2022.