Table 1. Transition probabilities, standard errors and data sources for figure 2.

Pathway	Probability	SE	Source
Initiation
To cigarette initiators	0.40	0.01	2006 NHIS22
To never user	0.56	0.01a	0.60 of population are never smokers minus 0.04 smokeless users; SE calculated from 95% CI of total smoking prevalence 18+22
To smokeless initiators	0.04	0.01	Average based on adult prevalence of smokeless NHIS 200029 (2.3%, 95% CI 2.1% to 2.5%) and 2003 teen current use (6.7%, 95% CI 5.2% to 8.2%) (Monitoring the Future and Youth Risk Behavior Survey, 200330) 2005 Substance Abuse and Mental Health Services Administration (SAMHSA) data estimate of 3.3% among ages 18 and older, 5.1% for 18–25 year olds31
Smokeless
To quit	0.17	0.01	Oregon adolescent males 1994–19996
To cigarettes	0.17	0.01
To smokeless	0.26	0.02
To dual user	0.40	0.02
Cigarettes
Stable	0.10	0.02	Adjusted to obtain current overall smoking prevalence (21%) and quit ratio (50.2%)22
Health concerned	0.50	0.02
Smokefree environment	0.30	0.02
Price sensitive	0.10	0.02
Health concerned
To quit	0.80	0.02	Adjusted to obtain current overall smoking
To cigarettes	0.20	0.02	prevalence (21%) and quit ratio (50.2%)22
To smokeless	0
To dual user	0
Smokefree environment
To quit	0.20	0.02	Adjusted to obtain current overall smoking
To cigarettes	0.80	0.02	prevalence (21%) and quit ratio (50.2%)22
To smokeless	0
To dual user	0
Price sensitive
To quit	0.10	0.02	Adjusted to obtain current overall smoking
To cigarettes	0.90	0.02	prevalence (21%) and quit ratio (50.2%)22
To smokeless	0
To dual user	0
Alternative patterns of smokeless use (using older national data with low levels of dual use)31
To quit	0.15	0.01	National young males in 1989 and 19938
To cigarettes	0.26	0.02
To smokeless	0.45	0.03
To dual user	0.14	0.01