date of the survey but, since they can vary over time, they are not included in the specifications for which I rely on retrospective data.<sup>11</sup> Section 4, however, by investigating whether or not the individuals are currently smoking as a dependent variable, will allow for controlling for income.

The price of cigarettes is also an important element of the smoking decision, even if tobacco is an addictive good (Becker, Grossman, and Murphy 1994). The National Health Interview Surveys do not include information about prices but the evolution of the real, after-tax price of a pack of 20 cigarettes from 1955 to 2000 is reconstructed in De Walque (2003). Despite a slight increase in the early 1970s, the real price of a pack of cigarettes has been fairly constant up to the early 1980s. Substantial increases in taxation after 1980 and the Tobacco Settlement in the late 1990s explain the rise in the real price to consumers. Figure 2 indicates that most of the differential in smoking prevalence by educational level is already present before the early 1980s and has occurred when there was no substantial variation in the real price of cigarettes.

# **_3. Smoking Initiation and Smoking Cessation_**

Smoking prevalence in the population is a stock that is defined by two flows: smoking initiation and smoking cessation. The upper panel of table 1 presents the results of a logit estimation where the dependent variable is an indicator for whether the individual ever started smoking. The estimation has been made for all individuals born between 1910 and 1969 and then separately for each 10-year birth cohort in that interval. In order to facilitate the interpretation of the results, I have indicated the age of each birth cohort in 1950 and in 1970, the starting and ending points of the period of gradual introduction of the information about the dangers of smoking. The average of the marginal coefficients, taken observation by observation, of the logit estimation are reported. In order to control for the sample composition issues discussed earlier, survey and year of birth dummies have been included. The other regressors are a set of dummies for the education categories (less than high school is excluded) and dummies for gender and race categories (female and white are excluded).

The results on the whole sample indicate that the likelihood of smoking decreases with schooling. The most striking results of the estimation, however, are found in the evolution of the coefficients on the education categories dummies when progressing across the birth cohorts. For the first two birth cohorts, born between 1910 and 1929, higher educational achievement does not necessarily lead to a lower probability of smoking. These two birth cohorts were aged between 21 and 40 in 1950 and between 41 and 60 in

> 11 Using the single 1990 National Health Interview Survey, I verified that considering the quantity of tobacco smoked does not change the conclusion (De Walque 2003). Controlling for income, the higher the level education among smokers, the smaller the amount of cigarettes smoked daily. This result reinforces my previous conclusions: more educated people are less likely to smoke and, if they smoke, they are smoking fewer cigarettes per day.

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