A Comment on the Economics of Labor Adjustment: Mind the Gap: Evidence from a Monte Carlo Experiment: Reply
回应Bayer（2009）对Cooper和Willis（2004）的批评，指出测量误差导致的非线性与总冲击水平直接相关，且CW的结论在未观测到缺口时依然稳健。
This note responds to Christian Bayer (2009). Cooper and Willis (2004), hereafter CW, find the aggregate nonlinearities reported in Ricardo Caballero and Eduardo Engel (1993) and Caballero, Engel, and John Haltiwanger (1997) reflect mismeasurement of the employment gap, not nonlinearities in plant-level adjustment. Bayer concludes the CW result is not robust to alternative aggregate shock processes. We concur, but argue that the nonlinearity created by mismeasurement does not disappear. Instead, it is directly related to the level of the aggregate shock. The CW findings are robust for the natural case of unobserved gaps.