Orzechowski and Walker (2011)). In the literature, there have been various attempts to clarify the causal effects of smoking on infant birth weight. Most previous empirical studies have evaluated the average effects of smoking or effects on the marginal distribution of potential infant birth weight focusing on the methods to overcome the endogeneity of smoking behavior. My analysis pays particular attention to the distribution of smoking effects on infant birth weight. The DTE conveys the information on the targets of anti-smoking policy, which is particularly important for this study, because the DTE can answer the following questions: ”how many births are significantly vulnerable to smoking ?” and ”who should the interventions intensively target?”. I make use of the cigarette tax increase in MA in January of 1993, which increased the state excise tax from $0 . 26 to $0 . 51 per pack, as an instrument to identify marginal distributions of potential birth weight acknowledging the presence of endogeneity in smoking behavior. In November 1992, MA voters passed a ballot referendum to raise the tax on tobacco products, and in 1993 the Massachusetts Tobacco Control Program was established with a portion of the funds raised through this referendum. The Massachusetts To- bacco Control Program initiated activities to promote smoking cessation such as media campaigns, smoking cessation counselling, enforcement of local antismoking laws, and educational programs targeted primarily at teenagers and pregnant women. The IV framework developed by Abadie, Angrist and Imbens (2002) is used to identify and estimate marginal distributions of potential infant birth weight for pregnant women who change their smoking status from smoking to nonsmoking in response to the tax increase. Henceforth, I call this group of people compliers. Based on the estimated marginal distributions, I establish sharp bounds on the smoking effects under the MTR assumption that smoking has adverse effects on infant birth weight. The related literature can be divided into three strands by their empirical strategy to overcome the endogenous selection problem. The first strand of the literature, including Almond et al. (2005), assumes that smoking behavior is exogenous conditional on observables such as mother’s and father’s characteristics, prenatal care information, and maternal medical risk factors. However, Caetano (2012) found strong evidence that smoking behavior is still endogenous after controlling for the most complete covariate specification in the literature. The second strand of the literature, including Permutt and Hebel (1989), Evans and Ringel (1999), Lien and Evans (2005), and Hoderlein and Sasaki (2011) takes an IV strategy. Permutt and Hebel (1989) made use of randomized counselling as an exogenous variation, while Evans and Ringel (1999), Hoderlein 32 5.2 Related Literature