Heterogeneity and Aggregation: Implications for Labor-Market Fluctuations: Comment
指出Chang和Kim（2007）的不完全资产市场模型因计算方法错误而得出低劳动生产率和工时相关性（0.23）及高劳动楔子波动（产出波动的76%），纠正后相关性升至0.80，劳动楔子波动降至产出的24%。
Chang and Kim (2007) develop an incomplete asset markets model incorporating discrete labor supply and idiosyncratic labor productivity. Their results resolve long-standing puzzles for business cycle models. Specifically, they produce a low correlation between aggregate hours worked and labor productivity (0.23) and a labor wedge with 76 percent the volatility of output. I show that these results arise from errors in their computational method. I resolve their model using a corrected method and find a strong, positive correlation between hours and productivity (0.80). Fluctuations in the labor wedge decrease to 24 percent of those in output.