I am a macroeconomist interested in macroeconomic policy, labor markets, business cycles, and international finance. My dissertation focuses on macro-labor economics and business cycles, while my broader research agenda spans applied macroeconomic and policy questions. Across these areas, I study how economic slack emerges, evolves, and affects aggregate outcomes, with applications to unemployment, underemployment, and recession measurement.
Contact: rzhan177@ucsc.edu CV
Working Papers
Beveridgean Unemployment Gap with Part-time Employment
Part-time work changes the amount of labor supplied by employed workers—and therefore changes the unemployment rate that is socially efficient.
Abstract
This paper extends the sufficient-statistics formula for efficient unemployment developed by Michaillat and Saez (2021) to account for part-time employment. I introduce two additional sufficient statistics that measure the share of part-time employment and part-time hours relative to full-time hours. Applying the framework to the United States (1951–2026) and Japan (1970–2025), I compare the effects of total part-time employment and involuntary part-time employment on efficient unemployment. Total part-time employment has substantially larger effects than involuntary part-time employment. While involuntary part-time employment provides information about labor-market slack, the main change in efficient unemployment comes from part-time work itself because part-time workers supply fewer market hours than full-time workers. Under the total part-time calibration, efficient unemployment averages 4.7% in the United States before COVID and 4.2% after COVID. In the Japanese application, the full-sample average is 2.7%. The distinction is especially important in Japan, where part-time employment is widespread and often reflects flexible work arrangements. These findings suggest that aggregate labor input, rather than involuntary part-time employment alone, is an important determinant of labor-market efficiency.
Recession Detection in Japan using Labor Market Data
joint work with Neha Sikand
Labor-market recession indicators can be adapted beyond the United States and identify Japanese recessions with high historical precision.
Abstract
Recession indicators are often viewed as U.S.-specific, raising the question of whether labor market–based rules such as the Sahm Rule and the Michez Rule can reliably detect recessions in other countries. To answer this, we evaluate whether such rules can be adapted to Japan by calibrating thresholds and smoothing parameters to Japanese labor market data. We construct a large set of 95,832 recession indicators combining unemployment and vacancy data. The selected classifiers are statistically perfect as they identify all 11 historical recessions in the 1970–2021 training period without generating any false positives. Among these, 193 classifiers lie on the anticipation–precision frontier. Restricting attention to the high-precision segment yields six classifiers with a standard deviation of detection errors below 3 months. The selected classifier ensemble signals recessions, on average, 0.06 months after their true onset. Overall, these findings suggest that slack-based labor market rules provide a general framework for improving real time recession detection across countries.
Recession Detection using Real Time GDP Data
joint work with Neha Sikand
Real-time GDP releases can provide a practical proxy for recession dating when official turning points are unavailable or delayed.
Abstract
This paper examines whether real-time GDP announcements can reliably identify business-cycle turning points. Using U.S. real-time GDP vintages from 1947 to 2021, we construct 4,356 recession indicators based on alternative smoothing methods and scaling variations. We then combine these indicators with alternative thresholds to generate 137,457 perfect recession classifiers. The selected classifiers identify all 12 historical recessions without generating false positives or false negatives. Restricting attention to the high-precision segment yields two classifiers with a standard deviation of detection errors below three months, while the selected ensemble signals recessions, on average, 3.04 months after their official onset. The framework accurately identifies recession episodes across vintages, suggesting that discrepancies in prior work may reflect limitations of traditional dating methods in addition to data revisions. Overall, the results indicate that real-time GDP announcements provide a practical proxy for NBER-style recession dating.
Work in Progress
Artisanal Labor in the Age of AI: Automation, Skill Scarcity, and Job Rationing
Develops a theoretical model to study how AI-driven technological change affects labor demand when consumers continue to value human-made, artisanal production. The project examines when automation complements rather than replaces skilled labor.
Unions and Unemployment: Rethinking Efficiency Wages as Bargained Working Conditions
This project examines how collective bargaining over workplace conditions influences productivity, employment, and labor-market efficiency through an efficiency-wage perspective.