Definition of a quit attempt: a replication test.

INTRODUCTION: The incidence of quit attempts is often used to measure the effects of tobacco control interventions. Many surveys of quit attempts require that the attempt last ≥24 hr, presumably to provide a more objective definition and to eliminate less serious attempts; however, this criterion may bias outcomes by excluding the more dependent quitters who cannot stop for 1 day despite a serious quit attempt.
METHODS: We examined the 2003 and the 2006-2007 Tobacco Use Supplements to the Current Population Survey to determine the prevalence of quit attempts that did and did not last 24 hr, both in the last 12 months and in one's lifetime among current daily smokers. We also tested the hypothesis that those unable to quit for 24 hr were the more dependent smokers.
RESULTS: Requiring quit attempts to last 24 hr excluded 6%-17% of smokers who stated they made a quit attempt. Whether smokers who could not quit for more than 24 hr were more dependent varied across survey, recall duration, and measure.
CONCLUSIONS: We conclude restricting quit attempts to those who have quit for 24 hr underestimates the prevalence of attempts. Whether those unable to quit for 24 hr are the more dependent smokers is unclear. Empirical tests of whether the addition of a 24-hr criterion increases reliability or validity are needed.