We show that within the Chicago Public Schools, both the introduction of NCLB in 2002 and the introduction of similar district-level reforms in 1996 generated noteworthy increases in reading and math scores among students in the middle of the achievement distribution but not among the least academically advantaged students. The stringency of proficiency requirements varied among the programs implemented for different grades in different years, and our results suggest that changes in proficiency requirements induce teachers to shift more attention to students who are near the current proficiency standard.

People are getting fat. The rise in obesity rate has been particularly pronounced in the United States since the middle of the 1970s, but has by now extended into many other areas of the world. Several sources of technological change have been singled out as potential explanations for why people have been gaining so much weight. Increased productivity in agriculture has lowered the relative price of food (Darius Lakdwalla, Tomas Philipson, and Jayanta Bhattacharya 2005) while innovations in food processing have reduced the time cost of preparing food (David M. Cutler, Edward L. Glaeser, and Jesse M. Shapiro 2003). Technological change has also affected how people spend their time, in a way that may systematically have reduced calories expended. First, physically less demanding jobs in the service sector have replaced physically more demanding jobs in agriculture and manu facturing. Second, the allocation of time across different activities has changed dramatically over the last few decades: people are spending less time working (decline in labor market work for men, decline in home production work for women) and more time in mainly sedentary forms of leisure, such as watching TV (Mark Aguiar and Erik Hurst 2007). While the focus so far has been on the rela tionship between how people spend their time and how many calories they expend, we argue in this piece that there might also be an inter esting relationship between how people spend their time and how many calories they consume. Motivating this question is a (at first glance) rather counterintuitive finding from the time use surveys: the fact that people, in the United States

Abstract Changes in the minimum wage may impact college enrollment and educational attainment. Using institutional data on college enrollment and program completion, we find that enrollment falls markedly among students at public two-year institutions in response to increases in the minimum wage. The largest enrollment effects are seen for those students who are enrolled part-time at community colleges. We find little evidence of negative effects on the attainment of certificates or degrees, suggesting that increases in the minimum wage are unlikely to divert students from degree attainment.

We examine how participation in social safety net programs differs by income-to-poverty levels, and how that relationship changed after the Great Recession. We define income-to-poverty based on the average of 2 years of merged CPS data, and investigate program participation among households with income less than 300 percent of poverty. We find changes in both the level and distribution of safety-net program participation during the Great Recession, with SNAP expanding most at the bottom, the EITC expanding most in the middle, and UI expanding most at the top of the income ranges that we investigate; TANF did not expand.