• September 2025
• Article

This paper evaluates a low-cost, customized soil nutrient management advisory service in India. As a methodological contribution, we examine whether and in which settings satellite measurements may be effective at estimating both agricultural yields and treatment effects. The intervention improves self-reported fertilizer management practices, though not enough to measurably affect yields. Satellite measurements calibrated using OLS produce more precise point estimates than farmer-reported data, suggesting power gains. However, linear models, common in the literature, likely produce biased estimates. We propose an alternative procedure, using two-stage least squares. In settings without attrition, this approach obtains lower statistical power than self-reported yields; in settings with differential attrition, it may substantially increase power. We include a “cookbook'' and code that should allow other researchers to use remote sensing for yield estimation and program evaluation.

• 2025
• Working Paper

Gross trading volumes in financial markets are large and far exceed return volatility. In contrast, “net volume”—trading from persistent portfolio reallocations—is substantially lower, as it excludes transitory round-trip trades. This observation reveals a fundamental tension: If return volatility is high, while net volume is low, then market participants either agree with each other (they are “homogeneous”), or they are not sensitive to price changes (they are “inelastic”), resulting in large price impacts of demand shocks. We formalize this tradeoff and demonstrate that the ratio of return volatility to net volume provides a lower bound on price impact, conditional on the level of investor heterogeneity. Using several measures from survey data, we document substantial heterogeneity, implying meaningful lower bounds on price impacts. The bounds align closely with reduced-form estimates from a variety of quasi-experiments, such as price impacts from index reconstitutions, whereas traditional liquidity measures based on gross trading volumes perform poorly. Our bounds prove particularly useful in settings where event-study evidence is difficult to obtain: we demonstrate how they vary over time, across individual assets, and at various levels of aggregation, including the aggregate stock market, and discuss their implications for asset pricing models and the macro-structure of financial markets. We argue in such markets with heterogeneous and inelastic investors, observed trading volumes are not peripheral but central to understanding asset price movements.

• 2025
• Working Paper

Sovereign debt yields have declined dramatically over the last half-century. Standard explanations, including aging populations and increases in asset demand from abroad, encounter difficulties when confronted with the full range of evidence. We propose an explanation based on a decline in inflation and default risk. We show that a model with sovereign default captures the decline in interest rates, the stability of equity valuation ratios, and the reduction in investment and output growth. Calibrations of the model post-Covid suggest that sovereign default risk may have returned.