Table 3

Time trends in tobacco use and its precursors

OutcomesChange in outcome over time
γ Coefficient (SE)*p Value
Smoking index0.268 (0.019)0.001
Intention to smoke0.130 (0.019)0.001
Friends smoking0.177 (0.019)0.001
Perception of smoking prevalence in the same grade0.207 (0.019)0.001
Positive social consequences0.003 (0.019)0.854
Negative social consequences−0.237 (0.019)0.001
Positive health consequences−0.041 (0.020)0.041
Negative health consequences−0.055 (0.019)0.006
Pro-tobacco industry attitude0.012 (0.019)0.518
Anti-tobacco industry attitude−0.015 (0.019)0.429
  • Values are the average change in outcome index values as students moved between grades 9 and10 to grades 11 and 12.

  • * γ One-zero (γ10) in equation 2.