{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T14:27:32Z","timestamp":1785421652718,"version":"3.56.0"},"reference-count":52,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T00:00:00Z","timestamp":1780272000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Humanities and Social Sciences Project of the Ministry of Education of China","award":["23YJA630004"],"award-info":[{"award-number":["23YJA630004"]}]},{"DOI":"10.13039\/501100020783","name":"Fujian Provincial Federation of Social Sciences","doi-asserted-by":"crossref","award":["FJ2024C024"],"award-info":[{"award-number":["FJ2024C024"]}],"id":[{"id":"10.13039\/501100020783","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100020783","name":"Fujian Provincial Federation of Social Sciences","doi-asserted-by":"crossref","award":["FJ2024C025"],"award-info":[{"award-number":["FJ2024C025"]}],"id":[{"id":"10.13039\/501100020783","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Fujian Provincial Innovation Strategic Project","award":["2025R0052"],"award-info":[{"award-number":["2025R0052"]}]},{"name":"Scientific Research Development Fund of Fujian University of Technology","award":["GY-S24011"],"award-info":[{"award-number":["GY-S24011"]}]},{"name":"Scientific Research Development Fund of Fujian University of Technology","award":["S900125040"],"award-info":[{"award-number":["S900125040"]}]},{"name":"Scientific Research Development Fund of Fujian University of Technology","award":["GJ-YB-26-02"],"award-info":[{"award-number":["GJ-YB-26-02"]}]},{"award":["GY-S24011"],"award-info":[{"award-number":["GY-S24011"]}],"id":[{"id":"https:\/\/ror.org\/03c8fdb16","id-type":"ROR","asserted-by":"publisher"}]},{"award":["S900125040"],"award-info":[{"award-number":["S900125040"]}],"id":[{"id":"https:\/\/ror.org\/03c8fdb16","id-type":"ROR","asserted-by":"publisher"}]},{"award":["GJ-YB-26-02"],"award-info":[{"award-number":["GJ-YB-26-02"]}],"id":[{"id":"https:\/\/ror.org\/03c8fdb16","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Systems"],"abstract":"<jats:p>Income inequality remains a central impediment to inclusive growth, yet whether government-led digital infrastructure programs mitigate or exacerbate distributional disparities is empirically contested. Exploiting the staggered rollout of China\u2019s \u201cBroadband China\u201d (BBC) demonstration cities as a quasi-natural experiment, this study employs a multi-period difference-in-differences (DID) framework on a panel of 281 prefecture-level cities spanning 2009\u20132022 to estimate the designation effects of national digital infrastructure policy under the DID identifying assumptions. After parallel-trends validation, permutation-based placebo tests, and propensity score matching, the baseline estimates indicate a dual distributional pattern: BBC designation is associated with a wider urban-rural income gap and lower within-prefecture nighttime-light-based spatial income inequality. Candidate-channel analysis provides evidence consistent with financial deepening and factor mobility as plausible pathways: expanded financial coverage and cross-regional labor reallocation are associated with spatial convergence, whereas asymmetric usage depth and selective labor mobility reinforce urban-rural divergence. Exploratory heterogeneity analysis across four institutional dimensions, officials\u2019 political promotion incentives, local fiscal capacity, traditional infrastructure endowments, and urban hierarchy, further shows that this distributional pattern varies across local contexts. Furthermore, this study extends the analytical lens to the spatial dimension by employing a spatial DID framework. The results identify significant cross-border externalities characterized by cross-prefecture spillovers associated with lower within-prefecture nighttime-light-based spatial income inequality in neighboring cities. These findings provide an integrated policy-evaluation framework that disentangles the complex, multidimensional distributional consequences of digital infrastructure investment, offering actionable insights for designing more equitable digital public policies in developing economies.<\/jats:p>","DOI":"10.3390\/systems14060625","type":"journal-article","created":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T06:17:31Z","timestamp":1780467451000},"page":"625","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Bridging the Map, Widening the Gap: Digital Infrastructure and Income Inequality"],"prefix":"10.3390","volume":"14","author":[{"given":"Huangxin","family":"Chen","sequence":"first","affiliation":[{"name":"School of Management, Fujian University of Technology, Fuzhou 350118, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-0900-5537","authenticated-orcid":false,"given":"Li","family":"Lin","sequence":"additional","affiliation":[{"name":"School of Economics and Management, Guangxi Normal University, Guilin 541006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zenghui","family":"Li","sequence":"additional","affiliation":[{"name":"Academy of Rural Development, School of Public Affairs, Zhejiang University, Hangzhou 330100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yi","family":"Shi","sequence":"additional","affiliation":[{"name":"Academy of Rural Development, School of Public Affairs, Zhejiang University, Hangzhou 330100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-1724-5773","authenticated-orcid":false,"given":"Su","family":"Lin","sequence":"additional","affiliation":[{"name":"School of Finance and Accounting, Fuzhou University of International Studies and Trade, Fuzhou 350202, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Piketty, T. (2014). Capital in the Twenty-First Century, Harvard University Press.","DOI":"10.4159\/9780674369542"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Milanovic, B. (2016). Global Inequality: A New Approach for the Age of Globalization, Harvard University Press.","DOI":"10.4159\/9780674969797"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"102616","DOI":"10.1016\/j.telpol.2023.102616","article-title":"Digital dividend or digital divide? Digital economy and urban\u2013rural income inequality in China","volume":"47","author":"Peng","year":"2023","journal-title":"Telecommun. Policy"},{"key":"ref_4","first-page":"103","article-title":"The impact of digital inclusive finance on urban\u2013rural income gap and its mechanism","volume":"25","author":"Liu","year":"2024","journal-title":"J. Hunan Agric. Univ. (Soc. Sci. Ed.)"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"106049","DOI":"10.1016\/j.frl.2024.106049","article-title":"The dual effects of digital inclusive finance on the urban-rural income gap: An empirical investigation in China\u2019s Yangtze River Delta region","volume":"69","author":"Wang","year":"2024","journal-title":"Financ. Res. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1257\/jel.20171452","article-title":"Digital economics","volume":"57","author":"Goldfarb","year":"2019","journal-title":"J. Econ. Lit."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1007\/s00168-015-0685-x","article-title":"Entrepreneurship and economic development in cities","volume":"55","author":"Audretsch","year":"2015","journal-title":"Ann. Reg. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"102012","DOI":"10.1016\/j.tele.2023.102012","article-title":"Unleashing the potential of mobile broadband: Evidence from Indonesia\u2019s underdeveloped regions on its role in reducing income inequality","volume":"82","author":"Ariansyah","year":"2023","journal-title":"Telemat. Inform."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1126\/science.1251868","article-title":"Skills, education, and the rise of earnings inequality among the \u201cother 99 percent\u201d","volume":"344","author":"Autor","year":"2014","journal-title":"Science"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Deng, X., Guo, M., and Liu, Y. (2023). Digital economy development and the urban-rural income gap: Evidence from Chinese cities. PLoS ONE, 18.","DOI":"10.1371\/journal.pone.0280225"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"103038","DOI":"10.1016\/j.telpol.2025.103038","article-title":"Digital empowerment and economic equity: Exploring the impact of household digital capability on income inequality","volume":"49","author":"Zhao","year":"2025","journal-title":"Telecommun. Policy"},{"key":"ref_12","unstructured":"Chen, Z., Yu, B., Yang, C., Zhou, Y., Yao, S., Qian, X., Wang, C., Wu, B., and Wu, J. (2026, January 05). An Extended Time-Series (2000\u20132023) of Global NPP-VIIRS-like Nighttime Light Data [Data Set]. Harvard Dataverse, Available online: https:\/\/dataverse.harvard.edu\/dataset.xhtml?persistentId=doi:10.7910\/DVN\/YGIVCD."},{"key":"ref_13","unstructured":"Negroponte, N. (1995). Being Digital, Alfred A. Knopf."},{"key":"ref_14","unstructured":"Brynjolfsson, E., and McAfee, A. (2014). The Second Machine Age: Work, Progress, and Prosperity in a Time of Brilliant Technologies, W. W. Norton & Company."},{"key":"ref_15","unstructured":"OECD (2001). Understanding the Digital Divide (OECD Digital Economy Papers No. 49), OECD Publishing."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"121359","DOI":"10.1016\/j.techfore.2021.121359","article-title":"The digital divide: A review and future research agenda","volume":"175","author":"Lythreatis","year":"2022","journal-title":"Technol. Forecast. Soc. Change"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1080\/09595238000185021","article-title":"The spread-backwash concept","volume":"14","author":"Gaile","year":"1980","journal-title":"Reg. Stud."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1131","DOI":"10.1080\/00343400903373601","article-title":"Count on the growth pole strategy for regional economic growth? Spread-backwash effects in greater Central China","volume":"44","author":"Ke","year":"2010","journal-title":"Reg. Stud."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"626","DOI":"10.1016\/j.eap.2021.10.013","article-title":"Blessing or curse? The effect of broadband Internet on China\u2019s inter-city income inequality","volume":"72","author":"Qiu","year":"2021","journal-title":"Econ. Anal. Policy"},{"key":"ref_20","unstructured":"Sen, A. (1999). Development as Freedom, Oxford University Press."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1488","DOI":"10.1257\/aer.20160696","article-title":"The race between man and machine: Implications of technology for growth, factor shares, and employment","volume":"108","author":"Acemoglu","year":"2018","journal-title":"Am. Econ. Rev."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"102387","DOI":"10.1016\/j.chieco.2025.102387","article-title":"Narrowing the digital divide: The growth and distributional effect of internet use on income in rural China","volume":"91","author":"Huang","year":"2025","journal-title":"China Econ. Rev."},{"key":"ref_23","first-page":"138","article-title":"A model of labor migration and urban unemployment in less developed countries","volume":"59","author":"Todaro","year":"1969","journal-title":"Am. Econ. Rev."},{"key":"ref_24","first-page":"126","article-title":"Migration, unemployment and development: A two-sector analysis","volume":"60","author":"Harris","year":"1970","journal-title":"Am. Econ. Rev."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Ma, S., and Mu, R. (Popul. Dev. Rev., 2025). Digital roots or digital routes? Broadband expansion and the rural\u2013urban migration in China, Popul. Dev. Rev., early view.","DOI":"10.1111\/padr.70042"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"100118","DOI":"10.1016\/j.pirs.2025.100118","article-title":"Regional institutions and the urban digital divide","volume":"104","author":"Caragliu","year":"2025","journal-title":"Pap. Reg. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1177\/14649934231173819","article-title":"How does internet infrastructure construction affect the urban-rural income gap? Evidence from a quasi-natural experiment in China","volume":"23","author":"Nie","year":"2023","journal-title":"Prog. Dev. Stud."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"102807","DOI":"10.1016\/j.jimonfin.2023.102807","article-title":"Financial structure and income inequality","volume":"131","author":"Brei","year":"2023","journal-title":"J. Int. Money Financ."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1111\/j.1467-9957.1954.tb00021.x","article-title":"Economic development with unlimited supplies of labour","volume":"22","author":"Lewis","year":"1954","journal-title":"Manch. Sch."},{"key":"ref_30","unstructured":"Fei, J.C.H., and Ranis, G. (1967). Development of the Labor Surplus Economy: Theory and Policy, Richard D. Irwin."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1781","DOI":"10.1093\/qje\/qjv028","article-title":"The skill complementarity of broadband Internet","volume":"130","author":"Akerman","year":"2015","journal-title":"Q. J. Econ."},{"key":"ref_32","first-page":"1401","article-title":"Measuring China\u2019s digital financial inclusion: Index compilation and spatial characteristics","volume":"19","author":"Guo","year":"2020","journal-title":"China Econ. Q."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"244","DOI":"10.1016\/0022-0531(70)90039-6","article-title":"On the measurement of inequality","volume":"2","author":"Atkinson","year":"1970","journal-title":"J. Econ. Theory"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Cowell, F.A. (2011). Measuring Inequality, Oxford University Press. [3rd ed.].","DOI":"10.1093\/acprof:osobl\/9780199594030.001.0001"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Weidmann, N.B., and Theunissen, G. (2021). Estimating local inequality from nighttime lights. Remote Sens., 13.","DOI":"10.3390\/rs13224624"},{"key":"ref_36","first-page":"100","article-title":"Mediating effects and moderating effects in causal inference","volume":"5","author":"Jiang","year":"2022","journal-title":"China Ind. Econ."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"126700","DOI":"10.1016\/j.jenvman.2025.126700","article-title":"From awareness to action: How climate attention drives the low-carbon transition in Chinese agriculture","volume":"392","author":"Shi","year":"2025","journal-title":"J. Environ. Manag."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"148050","DOI":"10.1016\/j.jclepro.2026.148050","article-title":"How does climate policy uncertainty impact green development of agriculture in China? A perspective from heterogeneous technological innovation","volume":"554","author":"Shi","year":"2026","journal-title":"J. Clean. Prod."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1146","DOI":"10.1016\/j.jpolmod.2020.02.004","article-title":"Impact of socio-economic infrastructure investments on income inequality in Iran","volume":"42","author":"Zolfaghari","year":"2020","journal-title":"J. Policy Model."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1016\/j.strueco.2024.12.002","article-title":"Does digital infrastructure exacerbate income inequality? Evidence from the Broadband China Strategy","volume":"72","author":"Liang","year":"2025","journal-title":"Struct. Change Econ. Dyn."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1016\/j.jeconom.2021.03.014","article-title":"Difference-in-differences with variation in treatment timing","volume":"225","year":"2021","journal-title":"J. Econom."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"2964","DOI":"10.1257\/aer.20181169","article-title":"Two-way fixed effects estimators with heterogeneous treatment effects","volume":"110","year":"2020","journal-title":"Am. Econ. Rev."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1016\/j.jeconom.2020.12.001","article-title":"Difference-in-differences with multiple time periods","volume":"225","author":"Callaway","year":"2021","journal-title":"J. Econom."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.jeconom.2020.09.006","article-title":"Estimating dynamic treatment effects in event studies with heterogeneous treatment effects","volume":"225","author":"Sun","year":"2021","journal-title":"J. Econom."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1405","DOI":"10.1093\/qje\/qjz014","article-title":"The effect of minimum wages on low-wage jobs","volume":"134","author":"Cengiz","year":"2019","journal-title":"Q. J. Econ."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1229","DOI":"10.3982\/ECTA6135","article-title":"Panel data models with interactive fixed effects","volume":"77","author":"Bai","year":"2009","journal-title":"Econometrica"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1203","DOI":"10.3982\/ECTA8968","article-title":"Eigenvalue ratio test for the number of factors","volume":"81","author":"Ahn","year":"2013","journal-title":"Econometrica"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1145","DOI":"10.1257\/aer.99.4.1145","article-title":"Salience and taxation: Theory and evidence","volume":"99","author":"Chetty","year":"2009","journal-title":"Am. Econ. Rev."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Mo, Y., Mu, J., and Wang, H. (2024). Impact and mechanism of digital inclusive finance on the urban\u2013rural income gap of China from a spatial econometric perspective. Sustainability, 16.","DOI":"10.3390\/su16072641"},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Wen, C., Xiao, Y., and Hu, B. (2024). Digital financial inclusion, industrial structure and urban\u2013rural income disparity: Evidence from Zhejiang Province, China. PLoS ONE, 19.","DOI":"10.1371\/journal.pone.0303666"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1743","DOI":"10.1016\/j.jpubeco.2004.06.009","article-title":"Political turnover and economic performance: The incentive role of personnel control in China","volume":"89","author":"Li","year":"2005","journal-title":"J. Public Econ."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"102442","DOI":"10.1016\/j.jdeveco.2020.102442","article-title":"On the road: Access to transportation infrastructure and economic growth in China","volume":"145","author":"Banerjee","year":"2020","journal-title":"J. Dev. Econ."}],"container-title":["Systems"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-8954\/14\/6\/625\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T04:45:17Z","timestamp":1780548317000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-8954\/14\/6\/625"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,1]]},"references-count":52,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["systems14060625"],"URL":"https:\/\/doi.org\/10.3390\/systems14060625","relation":{},"ISSN":["2079-8954"],"issn-type":[{"value":"2079-8954","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,1]]}}}