I. Introduction
In recent years, various types of data are being used in economic analysis to complement government economic statistics. These data, called alternative data, include high-frequency sales data and logistics data, big data that captures various economic activities, and unstructured data such as images and text data that reflect economic activities. The advantage of using alternative data is not only the richness of the information, but also the quickness of the information. For example, in order to grasp economic changes quickly, consumption data based on credit card payment data, point-of-sale (POS) data at retail stores, and various business data are used in an integrated manner. The economic analysis using the alternative data have been conducted to estimate economic trends in real time and with high accuracy [1]–[3]. These have already become indispensable approaches to economic analysis in financial business.