Results from linear regression models predicting Graphic Health Warning Impact and Negative Pack Perceptions from month of interview in the plain packaging and comparison periods
| Comparison period (2011–2012) | Plain packaging period (2012–2013) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M | (SD) | β | 95% CI | p Value | M | (SD) | β | 95% CI | p Value | |||
| GHW impact | ||||||||||||
| Month | ||||||||||||
| Aug/Sept | NA | 2.67 | (0.93) | Ref | ||||||||
| Oct/Nov | 2.57 | (0.90) | Ref | 2.75 | (0.97) | 0.00 | −0.16 | 0.18 | 0.932 | |||
| Dec/Jan | 2.62 | (0.99) | −0.01 | −0.25 | 0.21 | 0.847 | 2.88 | (1.16) | 0.09 | 0.07 | 0.46 | 0.008 |
| Feb/March | 2.77 | (0.89) | 0.10 | −0.19 | 0.58 | 0.323 | 2.75 | (1.15) | 0.07 | −0.04 | 0.39 | 0.110 |
| April/May | 2.67 | (0.96) | −0.01 | −0.52 | 0.48 | 0.930 | 2.85 | (1.21) | 0.06 | 0.01 | 0.34 | 0.043 |
| Negative pack perceptions | ||||||||||||
| Month | ||||||||||||
| Aug/Sept | NA | 3.95 | (0.76) | Ref | ||||||||
| Oct/Nov | 4.03 | (0.60) | Ref | 3.96 | (0.75) | 0.02 | −0.47 | 1.06 | 0.449 | |||
| Dec/Jan | 4.11 | (0.64) | 0.06 | −0.43 | 1.46 | 0.286 | 4.50 | (0.63) | 0.27 | 2.74 | 4.18 | <0.001 |
| Feb/March | 4.08 | (0.59) | 0.03 | −1.40 | 1.88 | 0.775 | 4.58 | (0.61) | 0.37 | 3.14 | 4.75 | <0.001 |
| April/May | 4.03 | (0.69) | 0.07 | −1.61 | 2.80 | 0.598 | 4.64 | (0.63) | 0.40 | 3.87 | 5.21 | <0.001 |
Models controlled for demographics (sex, age, SES), smoking characteristics (frequency and level of smoking, 12 m quitting history), antismoking advertising activity (TARPs), and recent increases in cigarette costliness (% increase in past 12 weeks); M's and SD's are unweighted.
β, standardised coefficient; GHW, graphic health warnings; M, Mean (range 1–5).