Definitions and sample proportions for analysis variables (SEs in brackets)*
| Variable | Percentage of follow-up subsample n=347 |
|---|---|
| Variables measured at baseline in 2014 | |
| Recently vaped | 15.60 |
| Coded 1 for response of at least 1 to the question ‘During the last 30 days, on how many days (if any) have you used electronic cigarettes (e-cigarettes)?’. | (1.97) |
| See ‘great risk’ in smoking | 80.88 |
| Coded 1 for the response of ‘great risk’ to the question ‘How much do you think people risk harming themselves (physically or in other ways) if they smoke 1 or more packs of cigarettes per day?’. | (2.28) |
| Never smoked a cigarette | 71.05 |
| Coded 1 for the response ‘never’ to the question ‘Have you ever smoked cigarettes?’. | (2.49) |
| Recently smoked | 10.13 |
| Coded 1 for a response of ‘<1 cigarette a day’ or more to the question ‘How frequently have you smoked cigarettes in the past 30 days?’. | (1.68) |
| Female | 56.26 |
| Coded 1 for female respondents | (2.80) |
| Non-white† | 39.89 |
| Coded 1 for respondents who did not report that they were ‘white (Caucasian)’. | (2.77) |
| Binge drinking in past 2 weeks | 16.12 |
| Coded 1 for a response of at least one to the question ‘Think back over the last 2 weeks. How many times (if any) have you had 5 or more drinks in a row?’. | (2.00) |
| Recently smoked marijuana | 18.93 |
| Coded 1 for a response of at least 1 to the question ‘On how many occasions (if any) have you used marijuana (weed, pot) or hashish (hash, hash oil) during the last 30 days?’. | (2.09) |
| Variables measured at follow-up in 2015 | |
| See ‘great risk’ in smoking | 83.05 |
| Coded 1 for the response of ‘great risk’ to the question ‘How much do you think people risk harming themselves (physically or in other ways) if they smoke one or more packs of cigarettes per day?’. | (2.13) |
| Changed perception of risk of smoking away from ‘great risk’ | 11.12 |
| Coded 1 for respondents who saw ‘great risk’ in smoking at baseline but not at follow-up. | (1.82) |
| Smoked in last 12 months at 1-year follow-up | 21.75 |
| Coded 1 for respondents who responded ‘smoked once or twice’, or more, to the question ‘What best describes your cigarette smoking in the last 12 months?’. | (2.27) |
Baseline questions on cigarettes ask about lifetime and past 30-day smoking, but not smoking in the past year.
*Estimates weighted for oversample of 12th grade students with high levels of drug use and for attrition.
†More detailed measures of race/ethnicity are precluded by small sample size.