Tianyu Jiang

Research

Job Market Paper

Equalizing or Polarizing? Generative AI and Research Productivity in Economics
with Yuqing (Claire) Wang

Abstract: Does generative AI narrow or widen productivity gaps in research? We study the distributional effects of AI on research productivity in economics using evidence from three sources: NBER working-paper and publication records, text-based measures of LLM-assisted writing, and an original survey of 227 academic economists measuring AI use across research tasks. We first show that productivity gaps among NBER authors narrowed following ChatGPT’s release: authors without research assistants (RAs) published a larger share of papers in top-tier journals, while authors from smaller teams gained in working-paper output and publication speed. We then use the survey to examine how individual AI use affects research productivity. We find weak evidence that AI affects working-paper output on average, but there is substantial heterogeneity. Triple-difference estimates show that greater AI exposure narrows the output gap between researchers with and without RAs but widens the gap between senior and junior researchers. Selection into AI use follows a different pattern: junior researchers use AI more intensively and are more likely to use agentic tools. Thus, these differential productivity effects reflect differences in the returns to AI rather than selection into AI use. A model with diminishing returns to execution, increasing returns to conceptual capacity, and complementarity between the two explains how AI can alleviate disadvantages in research support while amplifying the returns to accumulated expertise. Over time, however, early convergence may give way to divergence as execution constraints recede and AI’s conceptual capabilities improve.

Working Papers

Politicians’ Time Horizon and Local Economic Performance: An Empirical Investigation

Abstract

By devising a measure of the politician’s expected tenure based on relative age and relative tenure, this paper estimates the causal effect of the provincial political leader’s time horizon (TH) on economic performance in China. To address the endogeneity concern of the constructed TH measure, I use the distance to mean tenure for each individual in each individual-position pair as an instrumental variable (IV). The IV is not correlated with individual-specific error component and individual-province match component by construction. I find that a politician one year younger and having served in the position for one year less compared to his/her peers achieves a 0.42 percentage point higher real GDP growth. Further investigation shows that this effect operates through long-term planning and increased investment in capital construction, with effects persisting for several years beyond the leader’s tenure. Evidence suggests the results are unlikely to be driven by short-term budget manipulation or promotion incentives.

Controversial Political Expression and Non-controversial Motives: Experimental Evidence from China

Abstract

We study how the presence of a non-controversial motive alongside a controversial one influences individuals’ decisions to publicly expressing controversial political views. In an experiment with college students in China, we investigate whether students would sign a controversial petition protesting Japan’s release of Fukushima wastewater and calling for a boycott of Japanese products. Before signing, participants received information treatments that manipulated their perceptions of the prevalence of a non-controversial motive (environmental concerns) and a controversial motive (anti-Japan beliefs). The results show that the information treatment targeting the non-controversial environmental motive increases signing rates by 17 percentage points when decisions are public, but has no effect when private. We observe no significant effect from manipulating the controversial motive. These findings suggest that shaping beliefs about others’ motives can substantially influence controversial expression by altering perceived social costs, underscoring the power of non-controversial rationales in facilitating controversial expression.

Work in Progress