Asian Pacifc Journal of Cancer Prevention, Vol 14, 2013 6563 DOI:http://dx.doi.org/10.7314/APJCP.2013.14.11.6563 Tobacco Use and Quit Behaviour Assessment in the Global Adult Tobacco Survey: Invalid Responses and Implications Asian Pac J Cancer Prev, 14 (11), 6563-6568 Introduction Quit attempt among tobacco users is an important tobacco cessation behaviour indicator (Starr et al., 2005; Fong et al., 2006; Global Adult Tobacco Survey Collaborative Group, 2011). It has been defned as an activity by a tobacco user in which the person tries to quit (stop using) with the intention of never using it again (IARC, 2008). The numerator of this indicator includes current tobacco users (smokers/smokeless users) who tried to quit during the past 12 months and former tobacco users (smokers/smokeless users) who have been abstinent for <12 months. The denominator includes the total number 1 Project STEPS, Public Health Foundation of India, New Delhi, and Heath Systems Research India Initiative, Bangalore, 2 Department of Community Medicine, Maulana Azad Medical College, 4 Department of Epidemiology and Public Health, University College London, U.K. and Public Health Foundation of India (PHFI), PHD House, Siri Fort Institutional Area, New Delhi, 3 Indian Institute of Public Health, Bhubaneswar, India *For correspondence drpratapjena@gmail.com Abstract Background: Tobacco use and quit attempts are two key indicators of the Global Adult Tobacco Survey (GATS) that assess quit attempts among current as well as former tobacco users. The relevant data have inherent policy implications for tobacco cessation programme evaluation. This study aimed to review the concepts of quit attempt assessment and quantifying invalid responses considering GATS-India data. Materials and Methods: GATS assessment of tobacco use and quit attempts were examined in the current literature. Two categories of invalid responses were identifed by stratifed analysis of the duration of last quit attempt among current users and duration of abstinence among former users. Category A included absolute invalid responses when time- frame of assessment of current tobacco use and less than former tobacco use were violated. Category B included responses that violated the unit of measurement of time. Results: Current daily use, current less than daily use and former use in GATS were imprecisely defned with overlapping of time-frame of assessment. Overall responses of 3,102 current smokers, 4,036 current smokeless users, 1,904 former smokers and 1,343 former smokeless users were analyzed to quantify invalid responses. Analysis indicated overall 21.2% (category A: 7.32%; category B: 17.7%) and 22.7% (category A: 8.05%; category B: 18.1%) invalid responses among current smokers and smokeless users respectively regarding their duration of last quit attempt. Similarly overall 6.62% (category A: 4.7%; category B: 2.3%) and 10.6% (category A: 8.6%; category B: 3.5%) invalid responses were identifed among former smokers and smokeless users respectively regarding their duration of abstinence. Conclusions: High invalid responses for a single assessment are due to the imprecise defnition of current use, former use and quit attempt; and failure to utilize opportunity of direct data entry interface use during the survey to validate responses instantly. Redefning tobacco use and quit attempts considering an appropriate timeframe would reduce invalid responses. Keywords: Quit attempt - validity - global adult tobacco survey - India RESEARCH ARTICLE Tobacco Use and Quit Behaviour Assessment in the Global Adult Tobacco Survey (GATS): Invalid Responses and Implications Pratap Kumar Jena 1 *, Jugal Kishore 2 , Sanghamitra Pati 3 , Bidyut Kanti Sarkar 4 , Sagarika Das 5 of current tobacco users, and former tobacco users who have been abstinent for <12 month (GTSS, 2009). This indicator has been derived from two separate questions of the GATS survey asked of current and former tobacco users in order to avoid underestimation when only current users are included for assessment. While tobacco use represents falling into the captive of tobacco dependence, the quit attempt represents its opposite dimension. Both the tobacco use prevalence and quit attempt among tobacco users are the measures of effectiveness of tobacco control policies (IARC, 2008). IARC (2008) review on natural history of tobacco use indicates that non smoker would undergo a series of steps