JEL codes: J30, J41 Meng (2017) analyzes survey data from China to assess the impact of China's 2008 Labor Contract Law on the employment outcomes of migrant workers in China. Her results suggest that the Law had mixed impacts, likely negatively affecting wages and working hours, but positively affecting social insurance participation. Meng finds that many outcomes targeted by the Law are strongly influenced by macro labor conditions as measured by city wages and unemployment rates, rightly pointing out that studies must take macro-factors into account to correctly assess the impact of labor regulations. She also points out that changes over time in the impact of labor contracts on employment outcomes could result from changes in selectivity of what types of people have jobs with labor contracts rather than the impacts of the Law itself, and presents evidence that such bias leads to an overestimation of the impacts of the Law.Meng is up front about the difficulty of cleanly identifying the impact of the Law because it was implemented nationally at one point in time. As a result, any before-after comparisons could merely reflect changing labor market conditions in China. There are also limitations imposed by the available data. The Rural-Urban Migration in China Project (RUMICI) migrant panel data in 15 cities only began in 2008, after the law was implemented. Thus, before-after comparisons must rely either on repeated cross-sectional data using RUMICI pretest data on migrants from 4 cities in 2007 or the population mini-census data in 2005, which used a different sampling approach. Another major limitation is that the RUMICI survey did not ask questions about whether workers had signed labor contracts until 2010. As a result, Meng uses formal employment (permanent or fixed term employment, rather than temporary employment) as a proxy for having a labor contract for the years before 2010. This is a very crude and probably unsatisfactory approach given that it conflates contract status with other job attributes. Other research has found that the share of "formal" workers with labor contracts increased after the Law was implemented (Gallagher et al., 2014).The difference-in-difference specification comparing impacts on formal employees and temporary employees while controlling for macro labor conditions produces quite different †Correspondence: