Weiss 2006.

Methods	Cohort Study Baseline: Unknown (prior to 2005) Follow‐up: 12 and 24 months Site: Los Angeles metropolitan area, USA Research Question: (1) to what extent does exposure to tobacco media affect susceptibility to smoking over time? (2) Does anti‐tobacco media exposure interact with pro‐tobacco media exposure in relationship to smoking susceptibility in adolescents? (3) Does ethnicity or acculturation affect the relationship between tobacco‐related media exposure and intention to smoke? Analysis: Logistic regression models using hierarchical generalized linear models (to cluster students within classrooms, within schools) with gender, ethnicity, acculturation status, pro‐tobacco and anti‐tobacco media exposure, and experimental conditions as covariates to predict smoking susceptibility by later grades. Interaction and moderation effects of pro‐ and anti‐tobacco media exposure on ethnicity, acculturation and immigration status were tested using Chi‐square analysis.
Participants	3,190 6th grade students at baseline; 2,822 7th grade students at year 1; and 2,561 8th grade students at year 3. Total of 2,046 student with complete data at each follow‐up and were non‐susceptible non‐smokers at baseline. Participants were from 24 schools with grades 6‐8, located in Southern California with student population comprised of at least 25% Hispanic or at least 25% Asian American. Survey Method: self‐reported, pencil‐and‐paper surveys administered in classrooms.
Interventions	Pro‐tobacco media exposure was measured at baseline with two items: " when you watch TV, how often do you see people smoking" and "When you go to a small market, convenience store (like 7/11) or gas station mini‐mart (like AM/PM), how often do you see advertisements for cigarettes?" Response options were rated on a 6‐point scale (1= Alot to 4= Never, plus 5= I never watch TV/go to a small market, store or mini‐mart, and 6= I don't know) Pro‐tobacco media exposure was then re‐coded into four categories: 0 = non‐exposure to both TV smoking and market advertising; 1= exposure to either TV smoking or market advertising; 2= exposure to both TV smoking and market advertising; and 3= other (for those who answered options 5, 6 or missing). Anti‐tobacco media exposure was assessed at baseline with the question: In the last month, how many TV commercials have you seen about NOT smoking? Responses were rated on a 4‐point scale (1=none to 4= a lot). The scores for anti‐tobacco exposures were then re‐coded into exposure versus non‐exposure to TV commercials. Acculturation was measured using the eight‐item Acculturation, Habits, and Interests Multicultural Scale for Adolescents (AHIMSA) to assess one of four acculturation statuses. The questions such as "I am most comfortable being with people from..." and "The holidays I celebrate are from..." had four response options: a) The United States (assimilation orientations); b) The country my family is from (separation orientations); c) both (integration orientation); and d) Neither (marginalization orientation). Each student was assigned to one of the four orientation categories based on his/her most commonly selected response.
Outcomes	Baseline smoking status was classified by two categories, Non‐susceptible non‐smokers and all others (including susceptible non‐smokers and smokers). Smoking susceptibility was captured using the question "At any time in the next year (12months), do you think you will smoke a cigarette?" Students responding "No, definitely not" out of a four‐point scale were coded as non‐susceptible non‐smokers, all other responses (Maybe no, Maybe yes, and Yes definitely) were coded as susceptible non‐smokers)
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