Huajun Zhang, Qin Huo, Rui Jing, Meng Dong
Clinical analysis of acute poisoning in children
BMC pediatrics
harlem childrens zone hcz ambitious social experiment combines community programs charter schools provide first empirical test causal impact hcz charters educational outcomes lottery instrumental variable identification strategies suggest effects attending hcz middle school enough close blackwhite achievement gap mathematics effects elementary school large enough close racial achievement gap mathematics ela conclude evidence suggests highquality schools enough significantly increase academic achievement among poor community programs appear neither necessary sufficient jel h75 i21 i28 j13 r23