| Literature DB >> 24251415 |
Ryota Nakamura1, Marc Suhrcke, Rachel Pechey, Marcello Morciano, Martin Roland, Theresa M Marteau.
Abstract
AIMS: To evaluate the impact of the 2011 Scottish ban on multi-buy promotions of alcohol in retail stores. DESIGN ANDEntities:
Keywords: Alcohol consumption; Scottish ban on multi-buys; alcohol purchasing; difference-in-differences analyses; price promotions; regulation
Mesh:
Year: 2014 PMID: 24251415 PMCID: PMC4227589 DOI: 10.1111/add.12419
Source DB: PubMed Journal: Addiction ISSN: 0965-2140 Impact factor: 6.526
Impact of the multi-buy ban on the volume of alcohol purchased per quarter in Scotland (difference-in-differences estimation)
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | |
|---|---|---|---|---|---|---|---|---|---|---|
| Beer and cider | Wine | Spirits | Flavoured alcoholic beverages | Total pure alcohol | ||||||
| Scotland | England and Wales | Scotland | England and Wales | Scotland | England and Wales | Scotland | England and Wales | Scotland | England and Wales | |
| Panel A: January 2011–June 2012 (pre-ban period: January 2011–September 2011; post-ban period: October 2011–June 2012) | ||||||||||
| Pre-ban | Pre-ban | Pre-ban | Pre-ban | Pre-ban | ||||||
| Log volume (raw volume | 8.341 (4192.3 ml) | 8.511 (4967.7 ml) | 7.907 (2716.7 ml) | 7.837 (2533.4 ml) | 7.111 (1225.9 ml) | 6.917 (1009.3 ml) | 6.701 (813.2 ml) | 6.566 (710.2 ml) | 4.029 (56.2 units) | 3.970 (53.0 units) |
| Post-ban | Post-ban | Post-ban | Post-ban | Post-ban | ||||||
| Log volume (raw volume) | 8.463 (4735.1 ml) | 8.588 (5364.7 ml) | 8.009 (3008.0 ml) | 7.963 (2872.8 ml) | 7.350 (1556.7 ml) | 7.224 (1371.8 ml) | 6.657 (778.1 ml) | 6.546 (696.2 ml) | 4.258 (70.7 units) | 4.206 (67.1 units) |
| Difference of log volume: post-ban–pre-ban | 0.122 | 0.077 | 0.102 | 0.126 | 0.239 | 0.307 | −0.044 | −0.020 | 0.230 | 0.236 |
| Difference-in-differences (95% Cl): Scotland–England and Wales | 0.045 (−0.030, 0.119) | −0.024 (−0.077, 0.029) | −0.068 (−0.132, −0.004) | −0.024 (−0.197, 0.149) | −0.006 (−0.059, 0.046) | |||||
| Percentage change (%) | 4.59% | −2.36% | −6.57% | −2.39% | −0.62% | |||||
| Absolute change (ml) | 192.4 ml | −64.2 ml | −80.6 ml | −19.4 ml | −0.3 units | |||||
| Observations (number of households) | 24 372 (12 186) | 25 490 (12 745) | 16 072 (8 036) | 2898 (1449) | 36 610 (18 305) | |||||
| Panel B: control sample: January 2010–June 2011 (pre-ban equivalent period: January 2010–September 2010; post-ban equivalent period: October 2010–June 2011) | ||||||||||
| Pre-ban equivalent | Pre-ban equivalent | Pre-ban equivalent | Pre-ban equivalent | Pre-ban equivalent | ||||||
| Log volume (raw volume) | 8.462 (4727.8 ml) | 8.602 (5440.2 ml) | 7.939 (2804.2 ml) | 7.864 (2601.8 ml) | 7.140 (1261.0 ml) | 6.912 (1004.1 ml) | 6.578 (719.3 ml) | 6.644 (768.0 ml) | 4.147 (63.2 units) | 4.029 (56.2 units) |
| Post-ban equivalent | Post-ban equivalent | Post-ban equivalent | Post-ban equivalent | Post-ban equivalent | ||||||
| Log volume (raw volume) | 8.474 (4787.0 ml) | 8.601 (5439.5 ml) | 8.026 (3058.6 ml) | 7.954 (2846.0 ml) | 7.386 (1613.2 ml) | 7.246 (1401.8 ml) | 6.813 (910.1 ml) | 6.687 (802.3 ml) | 4.296 (73.4 units) | 4.231 (68.8 units) |
| Difference of log volume: post-ban equivalent–pre-ban equivalent | 0.012 | −0.001 | 0.087 | 0.090 | 0.246 | 0.334 | 0.235 | 0.043 | 0.149 | 0.203 |
| Difference-in-differences (95% CI): Scotland– England and Wales | 0.013 (−0.043, 0.068) | −0.003 (−0.042, 0.036) | −0.087 (−0.143, −0.032) | 0.192 (−0.004, 0.387) | −0.054 (−0.097, −0.011) | |||||
| Observations (number of households) | 21 892 (10 946) | 23 722 (11 861) | 14 810 (7 405) | 2480 (1240) | 33 424 (16 712) | |||||
| Difference-in-difference-in-differences (95% CI) | 0.032 (−0.060, 0.125) | −0.021 (−0.083, 0.041) | 0.019 (−0.070, 0.109) | −0.216 (−0.479, 0.047) | 0.048 (−0.018, 0.114) | |||||
| Percentage change (%) | 3.28% | −2.08% | 1.95% | −19.41% | 4.87% | |||||
| Absolute change (ml) | 137.6 ml | −56.5 ml | 24.0 ml | −157.8 ml | 2.7 units | |||||
| Total observations | 46 264 | 49 212 | 30 882 | 5378 | 70 034 | |||||
Raw volume refers to the back-transformed mean of log-scaled volume, i.e. the geometric mean of volume. As the distribution of raw volume of alcohol purchased is highly right-skewed (see Supporting information Fig. S1), geometric mean is smaller than the usual arithmetic mean. Table S2 provides the arithmetic mean of raw volume purchased.
Absolute change is evaluated using the estimated percentage change for the back-transformed mean volume for Scottish households in the pre-ban period in 2011 (January 2011–September 2011). All analyses were conducted based on the log-scaled volume, therefore the predicted absolute change in the table does not necessarily equate to the simple differences of the back-transformed mean log-scaled volume. Percentage change was calculated using the estimated treatment effect with the log-scaled outcome variable, i.e. percentage change = exp(τ) – 1, where τ is the point estimate of the treatment effect. The absolute change is evaluated at the baseline (Scotland pre-ban). In column (9) and (10), units of alcohol are calculated by the following: unit = volume (ml) × alcohol by volume (ABV). In the aggregation of alcohol from the four categories, average ABV for each category was used in the analysis, following a UK Office of National Statistics document 25. CI = confidence interval.
Figure 1Trends in alcohol purchasing in Scotland, England and Wales 2010–12. Vertical lines in the figures represent the introduction of the multi-buy ban. Annual rises in sales in quarter 4 relate to Christmas sales (trends excluding the Christmas period are shown in the Supporting information in Fig. S3). The volume of pure alcohol is the aggregated volume of alcohol purchased from the four categories, weighted using average alcohol by volume (ABV) of each category. Total pure alcohol is measured by log volume of alcohol units