Third-tier cities are large and medium-sized cities of strategic significance, more economically developed, and with larger economic totals that are comprehensively evaluated based on a number of indicators, including the size of the built-up area, the number of people in the city, the level of economic development, and the total GDP.

Fourth-tier cities are mostly medium-sized cities with more ordinary city size, economic and social development level and transportation construction. Most of the fourth-tier cities are predominantly prefecture-level cities, and also include the provincial capitals, capitals and autonomous regions of individual provinces and autonomous regions.

Third-tier Cities Selection Criteria:

On May 29, 2020, CBN-New Tier 1 Cities Research Institute released the "2020 Cities Business Charm Ranking". The "2020 City Business Charm Ranking" evaluates cities according to five dimensions: concentration of business resources, urban hubs, activity of urbanites, diversity of lifestyles, and future plasticity. CBN-New Tier 1 Cities Research Institute ranked 337 cities above prefecture level in China based on branded commercial data, user behavior data from Internet companies and city big data from data organizations. The list is divided into "Tier 1, New Tier 1, Tier 2, Tier 3, Tier 4 and Tier 5".

Reference: Baidu Encyclopedia - Third-tier Cities

Reference: Baidu Encyclopedia - Fourth-tier Cities