Steering teens safe: a randomized trial of a parent-based intervention to improve safe teen driving

BMC Public Health

Table 3 Intervention effects on risky driving mean scores for teens, by treatment group

		Risky driving score		Gamma generalized linear model estimates
	n	One month average (estimated)	Six month average (estimated)	(Estimated mean ratio)^a	Confidence level at which statistical significance reached
	n	One month average (estimated)	Six month average (estimated)	(Estimated mean ratio)^a	95% CI	90% CI	85% CI
Model 1: Overall groups
Control	75	5.68	7.91	Ref.	————	————	————
Intervention	70	4.49	6.26	0.79	(0.55, 1.15)	(0.58, 1.08)	(0.60, 0.99)
Upper to lower confidence limit ratio (CLR)					2.1	1.9	1.7
Model 2: Intervention/Talking Topics Score
Control/Low score	34	6.72	8.94	Ref.	————
Control/High score^b	41	4.63	6.15	0.76	(0.49, 1.18)
Intervention/Low score^b	34	5.13	6.82	0.69	(0.46, 1.03)
Intervention/High score^b	36	3.94	5.24	0.58	(0.36, 0.94)
Model 3: Intervention/Talking success score
Control/Low score	63	9.32	4.16	Ref.
Control/High score^b	12	5.08	7.63	0.54	(0.27, 1.08)	(0.31, 0.97)
Intervention/Low score^b	5	10.51	8.61	1.12	(0.62, 2.05)	(0.68, 1.87)
Intervention/High score^b	65	5.31	4.34	0.56	(0.29, 1.09)	(0.32, 0.98)

^aBased on a repeated measures model that includes one- and six-month scores; ^bUpper-to-lower confidence limit ratios were under 2 for Talking Topics Scores and under 3 for Talking Success Scores.

ISSN: 1471-2458