**Table 4. Instrumental variable estimation: instrument for years of education is the risk of induction in Vietnam**

||1|2|3<br>First stag|4<br>e regression|5<br>|6|7|8|
|---|---|---|---|---|---|---|---|---|
|Dependentvariable||Years|ofeducatio|nabovehigh|school||College|and above|
|Induction risk|1.095***|<br>0.742***|1.64***|0.988***|1.779***|1.227***|<br>0.399***|0.284***|
||[4.86]|[2.64]|[7.24]|[3.52]|[7.68]|[4.25]|[8.07]|[4.67]|
|R-square|0.116|0.095|0.032|0.023|0.118|0.096|0.092|0.073|
|Observations|74,810|40,753|83,069|45,108|73,952|40,319|73,957|40,323|
|Instrumental variable r|egression||||||||
|Dependent variable|smoking<br>now|stopped<br>smoking|smoking<br>now|stopped<br>smoking|smoking<br>now|stopped<br>smoking|smoking<br>now|stopped<br>smoking|
|Years of education<br>above|0.076*|0.028|–0.06***|0.052|–0.038*|0.051|_|_|
|high school|[1.83]|[0.61]|[–3.10]|[1.38]|[–1.88]|[1.62]|_|_|
|College and above|_<br>|_<br>|_<br>|_<br>|_<br>|_<br>|–0.169*<br>[–1.82]|0.219<br>[1.57]|
|Male|_<br>0.058***<br>[3.64]|_<br>0.051***<br>[6.00]|_<br>0.081***<br>[6.98]|_<br>0.063***<br>[5.35]|_<br>0.078***<br>[6.83]|_<br>0.049***<br>[6.35]|<br>0.077***<br>[6.89]|<br>0.05***<br>[6.92]|
|Trendmale|0.00003|–0.003***|–0.0004|–0.003***|–0.0003|–0.003***|–0.0003|–0.003***|
||[0.05]|[–7.80]|[–0.85]|[–8.94]|[–0.64]|[–7.64]|[–0.55]|[–8.06]|
|Log family income in<br>1983$|–0.178***|0.093**|_|_|–0.078***|0.077***|–0.085***|0.086***|
||[–4.71]|[2.66]|||[–4.14]|[3.22]|[–5.21]|[4.47]|
|Vietnam veteran|<br>_<br>_|<br>_<br>_|_<br>0.057***<br>[7.16]|_<br>–0.003<br>[–0.56]|<br>0.063***<br>[7.57]|<br>–0.003<br>[–0.49]|<br>0.06***<br>[6.97]|<br>0.001<br>[0.12]|
|Black|<br>0.024|<br>–0.053***|0.027*|–0.094***|–0.0005|–0.05***|–0.0003|–0.05***|
||[1.24]|[–6.44]|[1.73]|[–4.14]|[–0.06]|[–6.59]|[–0.03]|[–7.19]|
|Other race|<br>–0.145***|<br>–0.008|<br>–0.044|<br>–0.039*|<br>–0.067**|<br>–0.019|<br>–0.069|<br>–0.013|
||[–4.85]|[–0.28]|[–1.41]|[–1.77]|[–2.29]|[–0.84]|[–2.45]|[–0.69]|
|R-square|(.)|0.088|0.052|0.074|0.068|0.089|0.065|0.084|
|Observations|74,810|40,753|83,069|45,108|73,952|40,319|73,957|40,323|

***, **, * denote statistical significance at the 1%, 5% and 10% confidence levels, respectively.

(.) denotes negative R-square.

_ indicates that the variable was not included in the regression.

_Note_ : Analysis from smoking histories from the 1983, 1985, 1987, 1988, 1990, 1991, 1992, 1994, and 1995 National Health Interview Surveys for individuals age 25 and above at the time of the survey. Individuals born between 1937 and 1956. Linear regression model, where the dependent variable is current smoking behavior (odd columns) or smoking cessation for individuals who ever smoked (even columns). Robust t-statistics, clustered by birth cohort and gender, in square brackets. Birth cohort, age at interview and survey dummies included in all specifications. Trendmale, a dummy for male multiplied by a yearly trend where born in 1937=0, accounts for the trend in the difference in smoking behavior between males and females. See note 20 for details on the family income variable. The instrument for education is the induction risk in Vietnam faced by each birth cohort of males: it is the average yearly number of inductions in Vietnam during the years when that birth cohort was aged 19-22, divided by the size of that birth cohort. See note 23 for the data source for the instrument. Sample sizes vary across specifications as the Vietnam veteran status and the income variable might have been missing.

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