Supplementary Material for Measuring Economic Activity in China with Mobile Big Data

POI, or Points of Interest, refer to the geo-position points in maps. POI provided by Baidu Maps come from different sources. To assure the quality of POI, Baidu checked the validity of every POI and merged them into a standardized dataset. By comparing names and spatial coordinates of POI, calculating similarities and hashing, Baidu built its own POI dataset with a precision higher than 95%. All the POI were assigned with correct tags that described the attributes of locations. Each POI belongs to a standardized tag, and there are 30 categories and about 240 subcategories in total. In our research, we chose categories related to consumer activities: such as Shopping, Financial Institutions, Hotels, Tourism, Restaurants, Auto Services, and Entertainments.