## 4 Results  
### Measurement Results of RGTI, NQP, and CRCI  
This study is based on the measurement indicator system established in Section 3.1, measuring the development levels of CRCI, RGTI, and NQP across 30 provinces from 2013 to 2021. Figure 2 indicates that the regional CRCI was maintained at a high level of 0.750 to 0.820 throughout the study period. This phenomenon is considered to reflect the effectiveness of emission reduction policies in the construction industry and also reveals the complex interaction between the policy framework and technological drivers. During this period, the low-carbon transformation of the construction industry was promoted by the provinces through the implementation of innovative low-carbon technologies and the optimization of resource allocation, indicating that although the construction industry is a significant source of carbon emissions, a gradual improvement in overall carbon emission levels was achieved due to effective reduction measures [43]. In terms of RGTI, the upward trend is considered to be particularly evident, especially since 2015, when a significant acceleration was observed. Specifically, RGTI was observed to increase from 0.078 in 2015 to 0.175 in 2021; this change is considered to reflect the efforts made by provinces under the implementation of technology innovation policies and also to represent substantial progress in green technologies. Funds and resources were actively invested in green technology research and development, providing strong support for the industry and facilitating the achievement of carbon reduction targets.  
Similarly, NQP was noted to have steadily increased from 0.147 in 2013 to 0.224 in 2021, reflecting the effective improvement of new productivity among provinces during economic structural transformation and new economic models. This growth is considered to reflect the effectiveness of technological advances and industrial optimization, reinforcing the adaptability and resilience of the economy during the green transformation process. This suggests that new productivity may create conditions for further applications of green technologies, thereby facilitating their carbon reduction effects. This was found to be consistent with prior studies on the carbon reduction effects of new productivity [44]. The carbon reduction effects brought about by green technology innovation were observed to support carbon reduction in the construction industry, while the enhancement of new productivity indirectly was seen to strengthen the emissions reduction effects of green technologies through optimizing industry efficiency, production methods, and resource allocation. Based on the analysis above, the interactive relationship between CRCI, RGTI, and NQP is highlighted as showing a potential synergy in the process of transformation and upgrading. Higher CRCI levels are considered to complement the increases in RGTI and NQP. It is necessary for an econometric model to be constructed further to systematically quantify the impact mechanism of RGTI on CRCI and to explore the mediating effect of NQP, thus providing empirical support for the collaborative evolution of regional green technology innovation and carbon reduction in the construction industry from the perspective of new productivity.