Table 6

Predicted purchase rates under modelled hypothetical conditions (%, 95% confidence intervals)

If minors carried ID …
AlwaysRandom half of casesNever
Always11.5 (10.8 to 12.1) 7.6 (7.0 to 8.1) 3.7 (3.5 to 4.0)
If clerks asked ID …87% of cases (rate in experiment)17.7 (16.3 to 19.0)13.0 (11.8 to 14.2) 8.1 (7.2 to 9.0)
Random half of cases34.0 (32.3 to 35.7)21.4 (20.2 to 22.5)17.5 (16.3 to 18.7)