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Most papers that employ Differences-inDifferences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data on female wages from the Current Population Survey. For each law, we(More)
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We use a framework suggested by a model of rational addiction to analyze empirically the demand for cigarettes. The data consist of per capita cigarettes sales (in packs) annually by state for the period 1955 through 1985. The empirical results provide support for the implications of a rational addiction model that cross price effects are negative(More)
This paper provides a theoretical and empirical examination of the forces that contribute to the long-run growth in weight over time. We argue that technological change has induced weight growth by making home-and market-production more sedentary and by lowering food prices through agricultural innovation. We consider how technological change creates(More)
The authors modeled variability of force during continuous isometric contractions of the quadriceps femoris. Twenty adults (aged 25 +/- 6 years old) performed isometric leg extensions. Target forces were 11 percentages of maximum voluntary contraction (%MVC), ranging from 2 to 95%, and 5 absolute levels, from 25 to 225 N. The authors used standard deviation(More)
The views expressed herein are those of the author(s) and do not necessarily reflect the views of the National Bureau of Economic Research. ABSTRACT I explore the effects of education on nonmarket outcomes from both theoretical and empirical perspectives. Examples of outcomes considered include general consumption patterns at a moment in time, savings and(More)
We are grateful to Ann Facciolo for efforts in data inputting, to David T. Lykken, former Director of the Minnesota Twin/Family Registry (MTR) and the staff of the MTR for assistance in collecting the data that we use in this study, to audiences in presentations at the Arne Ryde Workshop on the and the referees for helpful comments on an earlier draft of(More)
This paper reexamines the empirical support for predictions that proposed cigarette tax or price increases will substantially reduce youth smoking. Part of the support for these predictions comes from evidence that higher taxes reduce aggregate tobacco sales and adult smoking rates. But taxes may have much different impacts on youth starting behavior than(More)
D uring the past 20 years, the United States has seen a dramatic increase in obesity. In 1991, only four states had obesity prevalence rates as high as 15 percent, and not a single state had a rate above 20 percent. By 2005, only five states reported rates below 20 percent, with 17 states registering rates equal to or above 25 percent (H. M. Blanck et al.(More)