Table 2

Estimated percentage change in quit attempts (the proportion of smokers who attempted to quit in the past 2 months) per 10% change in mass media expenditure from ARIMAX models

Quit attemptsUnadjustedAdjusted for covariates in table
Percentage change per 10% change in the exposure (95% CI), p ValuePercentage change per 10% change in the exposure (95% CI), p Value
Model 1
 Mass media expenditure (lag 0)−0.04 (-0.63 to 0.54), 0.883−0.03 (-0.62 to 0.56), 0.931
 Weekly spend tobacco (lag 4)−0.51 (-2.89 to 1.87), 0.677
 Tobacco control policies0.06 (-0.49;0.62), 0.830
 Best fitting modelARIMAX (0, 1, 1) (0, 0, 0)ARIMAX (0, 1, 1) (0, 0, 0)
 Non-seasonal (p)—ARNANA
  —MA<0.001<0.001
 Seasonal (p)—ARNANA
  —MANANA
 R20.0100.012
Model 2
 Mass media expenditure (lag 2)−0.05 (-0.67 to 0.56), 0.861−0.03 (-2.05 to 2.00), 0.979
 Weekly spend tobacco (lag 4)−0.51 (-2.94 to 1.93), 0.684
 Tobacco control policies−0.06 (-0.50 to 0.62), 0.831
 Best fitting modelARIMAX (0, 1, 1) (0, 0, 0)ARIMAX (0, 1, 1) (0, 0, 0)
 Non-seasonal (p)—ARNANA
 —MA<0.001<0.001
 Seasonal (p)—ARNANA
 —MANANA
 R20.0100.012
  • The assumption of normally distributed errors was met. When the lag for weekly tobacco spend was set to zero, results for mass media were similar in model 1 (β=−0.04 (–0.63 to 0.54) , p=0.882) or in model 2 (β=−0.05 (-0.66; to 0.56), p=0.864). Addition of MA or AR terms did not improve the models.

  • AR, autoregressive terms; ARIMAX, Autoregressive integrated moving average modelling with exogenous variables;MA, moving average terms.