Stevens 2000.

Methods	Randomized trial. Allocation concealment adequate (different days). Not a blinded observer.
Participants	Parents of children 3.5 to 8 years old and weighing 35‐80 pounds entering a retail toy store in Virginia.
Interventions	Participants either given pamphlet (P) and coupon (C) for seat, just a pamphlet, just a coupon, or no intervention (control group).
Outcomes	Purchase of booster seat increased 34% for the C+P group, 38% for P, 41% for C, and 3% for the control group. All respondents self‐reported using the booster seat every time child travelled.
Notes	Relatively brief follow‐up interval of 30 days. Unclear whether study had sufficient statistical power.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Low risk	A ‐ Adequate

A= adequate; B= unclear.