Table 1 Coding plan for the selected study variables

Outcome variable

Susceptibility to smoking

1. If one of your friends offered you a cigarette, would you smoke it?

1 = Definitely not

Students who are currently non-smokers and answered “Definitely not” to all 3 questions were coded as “non-susceptible”, and all other students were labeled as “susceptible” to smoking.

2 = Probably not

3 = Probably yes

3 = Probably yes

2. At any time during the next 12 months, do you think you will smoke a cigarette?

2. At any time during the next 12 months, do you think you will smoke a cigarette?

2. At any time during the next 12 months, do you think you will smoke a cigarette?

3 = Probably yes

4 = Definitely yes

3. Do you think, you will be smoking a cigarette 5 years now?

1 = Definitely not

2 = Probably not

3 = Probably yes

4 = Definitely yes

Independent variables

Age in years (categorical)

How old are you?

1 = 11 years old or younger

1 = Aged ≤ 13

2 = 12 years old

2 = Aged > 13

3 = 13 years old

4 = 14 years old

5 = 15 years old

6 = 16 years old

7 = 17 years old or older

Parents’ smoking status

Do your parents smoke?

1 = None

1 = None

2 = Both

2 = At least one parent smokes

3 = Father only

3 = I don’t know

4 = Mother only

5 = I don’t know

Friends’ smoking status

Do any of your closest friends smoke cigarettes?

1 = None of them

1 = Do not have friends who smoke

2 = Some of them

2 = Have friends who smoke

3 = Most of them

4 = All of them

Classes on harmful effects of smoking

During this school year were you taught in any of your classes about the dangers of smoking?

1 = Yes

1 = Did attend

2 = No

2 = Did not attend

3 = Not sure

Access to anti smoking media

During the past 30 days (1 month) how many anti-smoking media messages (e.g. television, radio, billboards, posters, newspapers, magazines, movies) have you seen?

1 = A lot

1 = Yes

2 = A few

2 = No

3 = None

Exposure to billboards cigarette marketing

During the past 30 days (1 month) how many advertisements for cigarettes have you seen on billboards?

1 = A lot

1 = Yes

2 = A few

2 = No

3 = None

Exposure to newspapers/magazines cigarette marketing

During the past 30 days (1 month) how many advertisements or promotions for cigarettes have you seen in newspapers or magazines?

1 = A lot

1 = Yes

2 = A few

2 = No

3 = None

Boys who smoke have “more or less friends

Do you think boys who smoke cigarettes have more or less friends?

1 = More friends

1 = More friends

2 = Less friends

2 = Less friends or no difference

3 = No difference from nonsmokers

Girls who smoke have more or less friends

Do you think girls who smoke cigarettes have more or less friends?

1 = More friends

1 = More friends

2 = Less friends

2 = Less friends or no difference

3 = No difference from nonsmokers

Boys who smoke are more or less attractive

Do you think smoking cigarettes make boys more or less attractive?

1 = More attractive

1 = More attractive

2 = Less attractive

2 = Less attractive or no difference

3 = No difference from nonsmokers

Girls who smoke are more or less attractive

Do you think smoking cigarettes make girls more or less attractive?

1 = More attractive

1 = More attractive

2 = Less attractive

2 = Less attractive or no difference

3 = No difference from nonsmokers

People who smoke are more or less comfortable at social gatherings

Does smoking cigarettes help people feel more comfortable at celebrations, parties or in other social gatherings?

1 = More comfortable

1 = More comfortable

2 = Less comfortable

2 = Less comfortable or no difference

3 = No difference from nonsmokers

Knowledge of harmful effects of smoking

Do you think cigarette smoking is harmful to your health?

1 = Definitely not

0 = Poor knowledge (response 1-3)

2 = Probably not

1 = Good knowledge (response 4)

3 = Probably yes

4 = Definitely yes

Knowledge of harmful effects of secondhand smoke

Do you think smoke from other people’s cigarette is harmful to you?

1 = Definitely not

0 = Poor knowledge (response 1-3)

2 = Probably not

1 = Good knowledge (response 4)

3 = Probably yes

4 = Definitely yes

Ever tried cigarette smoking

Have you ever tried or experimented with cigarette smoking, even one or two puffs?

1 = Yes

1 = Ever smoked

2 = No

0 = Never smoked