Transmission mechanism and evolutionary dynamics of construction cost index fluctuations

Purpose Amid accelerating urban integration and increasing intercity linkages in the construction market, the Construction Cost Index (CCI) exhibits significant co-movement and convergence across cities, undermining the effectiveness of localized regulatory policies. However, existing studies remain fragmented across spatial and temporal dimensions and lack a systematic understanding of intercity transmission mechanisms. This study aims to develop an integrated analytical framework to reveal the spatiotemporal transmission pathways and mechanisms of CCI fluctuations in China. Design/methodology/approach This study integrates Granger causality analysis with complex network theory to construct a spatiotemporally coupled CCI causality network. Using panel data from 34 major Chinese cities over the period 2016–2024, cities are modeled as nodes and causal relationships as edges to examine the network topology and its dynamic evolution. Findings The results reveal a multi-level transmission mechanism characterized by “core-driven, hub-mediated, and edge-responsive” dynamics. The network exhibits pronounced small-world properties, with high clustering and short average path lengths, enabling rapid diffusion of cost fluctuations. Structurally, strong intra-agglomeration linkages and relatively weak inter-agglomeration connections indicate clear modular differentiation. Over time, increasing network density and strengthening intercity connectivity reflect a deepening trend of regional integration. Originality/value This study overcomes the limitations of single-dimensional analyses by proposing a unified spatiotemporal framework for CCI transmission. It extends the application of complex network theory to construction economics and provides both theoretical insights and practical implications for differentiated regulation, market risk monitoring and coordinated urban governance.