Impact of the latent topics of policy documents on the promotion of new energy vehicles: empirical evidence from Chinese cities

Abstract As an important strategic emerging industry to promote sustainable economic development, new energy vehicles (NEVs) play multiple vital roles in energy saving and emission reduction and promote the transformation and upgrading of the automobile industry. China's government has formulated abundant policies to support the NEV industry. Existing studies do not pay enough attention to the latent information from NEV policy documents. This paper explores the latent topics of numerous NEV policy documents and their impact on promoting NEVs at the city level by combining the Latent Dirichlet Allocation (LDA) topic model and the econometric method. The results show that the latent topics of NEV policy documents can be categorized into charging infrastructure operation, promotion subsidy, and production support. The prevalence of the promotion subsidy topic is the strongest among the three types of topics. Total topic prevalences significantly promote NEV sales. The 2013 year is a turning point in policy preferences, and this change boosts NEV sales. The prevalence of promotion subsidy topic has an inverted U-shaped effect on NEV sales. The NEV sales will increase by 19% when the prevalence of production support topic increases by 1. Under the COVID-19, although the promotion subsidy policy is still dominant, the production support policy has been paid more attention. Finally, combining the development of China's NEV industry under the COVID-19 epidemic, the paper puts forward pertinent policy suggestions.