NBER Publications by Muzhe Yang

Since 1992, the Pennsylvania Health Care Cost Containment Council (PHC4) has published cardiac care report cards for coronary artery bypass graft (CABG) surgery providers. We examine the impact of CABG report cards on a provider's aggregate volume and volume by patient severity and then employ a mixed logit model to investigate the matching between patients and providers. We find a reduction in volume of poor performing and unrated surgeons' volume but no effect on more highly rated surgeons or hospitals of any rating. We also find that the probability that patients, regardless of severity of illness, receive CABG surgery from low-performing surgeons is significantly lower.

Do national borders and ethnicity contribute to market segmentation between and within countries? This paper uses unique and high-frequency data on narrowly-defined goods to gauge the extent to which a national border impedes trade between developing countries (Niger and Nigeria). Using a regression discontinuity approach, we find a significant price change at the national border, but one that is lower in magnitude than that found for industrialized countries. Yet unlike that literature, and in line with important characteristics of African economies, we investigate the role of ethnicity in mitigating and exacerbating the border effect. We find that a common ethnicity is linked to lower price dispersion across countries, yet ethnic diversity creates an internal border within Niger. The pri...