TABLE 2.

Two-sample iDID Wald estimates and their standard errors (in parentheses) using two successive birth cohorts (in %)

	1911–1920	1921–1930	1931–1940
Birth cohort	1921–1930	1931–1940	1941–1950
F-statistic	13.94	47.28	21.33
${\widehat{\beta }}_{\text{TSwald}}$	0.285 (0.089)	0.497 (0.076)	0.568 (0.127)

0Notes: F-statistic is the squared $z$-score, ${\widehat{\beta }}_{\text{TSwald}}$ defined in Section 4 estimates the ATE of smoking on lung cancer mortality. Abbreviations: ATE, average treatment effect; iDID, instrumented difference-in-differences.