## 3 Conceptual Model
SATUM's dependent variables are justified by their inclusion in the prior relevant literature. They are organized into four groups, which include the evolutionary stages of digitalization, which are access (infrastructure), use, and purposeful use (IT services and e-commerce) [6; 9]. These two purposeful use categories were selected due to the scarcity of purposeful use variables in government data sources, while they represent important dimensions of the digital economy. The groups are as follows. Infrastructure. Digital infrastructure is necessary for digital access, regardless of the type of device. It was included in the comprehensive digital divide model of [PERSON] [6] and mentioned in economic models [. Nationwide information infrastructure was related to IT governance and socioeconomic development for a large sample of developing nations [30]. In the Chinese literature, infrastructure was shown to have grown significantly since 2000, a trend that partly reflects the support from China's central government [31]. Rapid growth in the nation's technology infrastructure during the years 2004 to 2014 can be linked to planning and investment by the government and major telecom enterprises [10]. In the same decade, electrical output was shown to have a modest influence on the use of mobile phone subscribers in Chinese provinces [18]. The following infrastructure-dependent variables are included in the present study: length of optical cable lines, base stations of mobile phones, capacity of mobile phone exchange, and number of domain names. The latter was included in a provincial study of China using government data from 2006 to 2009 [18]. Use. In prior studies of the Chinese provinces, use factors served as dependent factors measured based on mobile devices [3; 12; 18; 32; 33], broadband [3; 19], the internet [12; 17; 18; 19], and web pages [17; 18]. Furthermore, these dependent variables for digital use have been frequently included in digital divide studies apart from China [6; 32; 33; 34]. Figure 1: SATUM model for digital inequalities in China, 2020. IT Services. IT services have rarely been included in digital divide research on China. They represent an important type of ICT purposeful use [35]. A study examined growth factors in domestic IT services in China and found that although technology infrastructure had grown substantially by 2012, IT services struggled to effectively support IT solutions [36]. However, the IT service revenue in China doubled in size from 2016 to 2023 to reach an estimated revenue of USD 25.6 billion in 2023 [37; 38]. A study of early IT services' growth in developing nations suggests that IT services are likely to vary between technologically and economically advanced provinces and those that are less developed [39]. E-Commerce. E-commerce utilization in China has been examined at different levels, including at the individual level in 2011 [13] the provincial level for 2013-2016 [2], and for e-shopping usage in 2017-2019 [14]. At the individual level, a 2011 survey showed access to e-commerce was related to age, college education, female sex, and rural migration [13]. A study of individual e-shopping adoption based on Alibaba online shopping data at the county level for 2017 indicated that the characteristics associated most strongly with e-shopping were a local delivery system, income, the college enrollment ratio, and transportation accessibility [14]. Our study builds on this base by analyzing sales through e-commerce, purchases through e-commerce, and percent of enterprises with e-commerce transactions. Next, we justify the independent variables, which are likewise divided into five groups of factors in the model. These groups are commonly seen in digital divide research, with the exception of knowledge production, which can be included through proxy variables. Demographic. Urban population is commonly incorporated into digital inequality models for China [3; 13]. It serves as a control for the large provincial differences in urban proportions.