Assessing the Temporal Stability of a Cigarette Purchase Task After an Excise Tax Increase for Factory-Made and Roll-Your-Own Smokers.
BACKGROUND
Cigarette purchase tasks (CPTs) are used increasingly to measure simulated demand curves for tobacco. However, there is currently limited information about the temporal stability of demand curves obtained from these tasks.


METHODS
We interviewed a sample (N = 210) of smokers in New Zealand both before and after a 10% increase in the tobacco excise tax that took effect on January 1, 2013. Participants were interviewed in November-December 2012 (wave 1) and February-March 2013 (wave 2). At each interview, participants completed a high-resolution CPT with 64 prices ranging from NZ $0.00 to NZ $5.00/cigarette, and questionnaires regarding their smoking habit.


RESULTS
Roll-your-own smokers had higher levels of nicotine dependence and tobacco demand based on CPT responses than factory-made smokers. Although demand curves for waves 1 and 2 were similar, intentions to purchase cigarettes were significantly less at wave 2 for three prices (NZ $0.85, NZ $0.90, and NZ $0.95) that were just higher than the actual price after the tax increase, for both roll-your-own and factory-made smokers. Measures of elasticity (α) derived from Hursh and Silberberg's model were significantly greater at wave 2 than wave 1, and there was a significant reduction in smoking habit as measured by cigarettes/day and the Fagerström Test for Nicotine Dependence at wave 2.


CONCLUSIONS
Purchase tasks can discriminate between smokers based on their tobacco preference, and although results are relatively stable over time, they depend on contextual factors such as the current real price for tobacco.
Department of Psychology, University of Canterbury, Christchurch, New Zealand; randolph.grace@canterbury.ac.nz.
Randolph C
RC
Grace
School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand;
Bronwyn M
BM
Kivell
Department of Psychology, University of Canterbury, Christchurch, New Zealand; Health New Zealand Ltd, Christchurch, New Zealand.
Murray
M
Laugesen
D000293:Adolescent; D000328:Adult; D005260:Female; D015438:Health Behavior; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D012907:Smoking / Q000191:economics / Q000453:epidemiology*; D016540:Smoking Cessation / Q000379:methods*; D011795:Surveys and Questionnaires; D013660:Taxes / Q000191:economics*; D062789:Tobacco Products / Q000191:economics*; D055815:Young Adult