Psychology of Addictive Behaviors
American Psychological Association
Methods assessing non-daily smoking are of concern because biochemical measures can not verify self-reports beyond 7 days. This study compares two self-reported smoking measures for non-daily smokers. A total of 389 college students, (48% female, 96% white, mean age of 19) smoking between 1 and 29 days out of the past 30, completed computer assessments in three cohorts with the order of administration of the measures counterbalanced. Values from the two measures were highly correlated. Comparisons of Timeline Follow-Back (TLFB) with the global questions for the total sample of non-daily smokers yielded statistically significant differences (p<.001), albeit small, between measures with the TLFB resulting on average in 2.38 more total cigarettes smoked out of the past 30 days, 0.46 less smoking days, and 0.21 more cigarettes smoked per day. Analyses by level of smoking showed that the discordance between the measures differed by frequency of smoking. Global questions of days smoked resulted in frequent reporting in multiples of five days, suggesting digit bias. Overall the two measures of smoking were highly correlated and equally effective for identifying any smoking in a 30-day period among non-daily smokers.
©2009 American Psychological Association