Table 1.

Construct definitions of hardcore smoking

Authors (year of publication)	Location	Data source and year(s)	Definition of hardcore	Notable exclusions	Hardcore prevalence as % of all smokers
Sorg et al. (2011) [6]	USA: Missouri	Missouri County level study, representative survey, 2007	No quit attempt in last 12 months	Smokers 25 years or under	7.8%
			CPD 15 or more
			Do not intend to quit in future
Lund et al. (2011) [5]	Norway	Statistics Norway: national cross-sectional survey, 1996–2009	No quit attempt in previous 12 months	Smokers 25 years or under	11% average 1996–2009 (max 16%, min 6%)
			No intention to quit in next 6 months
			Belief in continued smoking in 5 year's time
MacIntosh & Coleman (2006) [12]	UK	Secondary research data. General practice, Leicestershire, UK, 1995–96, 1998–99	Do not intend to quit in next month		16.1% (14.1–18.4)
			No desire to quit
			No quit attempts longer than 24 hours in past year
Jarvis et al. (2003) [13]	UK	UK Health Education Authority surveys, 1994–97	Do not intend to quit in future	Smokers 25 years or under	15.7%
			No desire to quit
			No quit attempts in past year
			less than 1 day without smoking cigarettes over past 5 years
Augustson & Marcus (2004) [4]	USA: national	1998–99 Tobacco Use Supplement to Current Population Survey (TUS-CPS)	Do not intend to quit in next 6 months	Smokers 25 years or under	13.7% of current smokers
			No previous quit attempt
			CPD 15 or more
			Daily smoker, with minimum 5 years smoking history
Emery et al. (2000) [14]	USA: California	California Tobacco Survey, 1996	Expect to never quit	Smokers 25 years or under	5.2%
			No quit attempts in past year
			CPD 15 or more

CPD: cigarettes per day.