On 2014 Aug 02, Hilda Bastian commented:

While safer driving by adolescents is a critically important issue - and further research in this area is definitely needed, the authors' conclusions about the effects of this intervention are overly positive.

The parent in these trials was overwhelmingly the mother (over 80%), mostly college-educated - and non-white families appear to have been under-represented. The participants responded to hearing about the trial rather than being actively recruited, and so were particularly highly motivated - and the trial couldn't reach its recruitment goal. Further, 16% of the intervention group were lost to follow-up at the primary outcome measurement point (compared with 6% in the control group).

Even with this highly motivated group in a trial setting, of an intervention more intensive than a large-scale program could be (Ramirez M, 2013), and with outcomes based solely on the adolescents' reports, pre-specified primary outcomes (trial registration record) did not achieve statistical significance. While the authors fairly attribute this to low recruitment making the trial under-powered, it isn't very encouraging. As the authors point out, there's no strong effect apparent here.

Presenting the adolescents' self-reported Risky Driving Score results as risk reduction percentages in the abstract risks giving people an exaggerated impression of effectiveness. The range of possible score isn't very wide, so even a small difference can be a substantial percentage. It would have been good if more details about the score were provided, given that it's a primary outcome measure and it was a trial-specific adaptation of an existing score.

It's great to see this trial published, even though it didn't meet its goals. But I don't agree with the authors' conclusion that statistical significance levels should be dropped low, in effect, because proven interventions are needed. The interventions that people would use need to make a real difference. As the authors point out, there is evidence that parents can make a difference to their adolescents' behaviors - to their list, I'd add influencing smoking (Thomas RE, 2007). But parents need to know where they could make the best effort, given the other options like Parent-Teen Driving Agreements (Zakrajsek JS, 2013) - or discouraging getting a license early (Ian R, 2001).

The authors indicate that future research will integrate more objective data, which presumably refers to the unreported data from 2010 for driving citations and crashes in this trial. That will be vital to put this self-reported data on surrogate outcomes in perspective. Access for others to the intervention materials may be important for others in the field (Glasziou P, 2010).

On 2014 Aug 02, Hilda Bastian commented:

While safer driving by adolescents is a critically important issue - and further research in this area is definitely needed, the authors' conclusions about the effects of this intervention are overly positive.

The parent in these trials was overwhelmingly the mother (over 80%), mostly college-educated - and non-white families appear to have been under-represented. The participants responded to hearing about the trial rather than being actively recruited, and so were particularly highly motivated - and the trial couldn't reach its recruitment goal. Further, 16% of the intervention group were lost to follow-up at the primary outcome measurement point (compared with 6% in the control group).

Even with this highly motivated group in a trial setting, of an intervention more intensive than a large-scale program could be (Ramirez M, 2013), and with outcomes based solely on the adolescents' reports, pre-specified primary outcomes (trial registration record) did not achieve statistical significance. While the authors fairly attribute this to low recruitment making the trial under-powered, it isn't very encouraging. As the authors point out, there's no strong effect apparent here.

Presenting the adolescents' self-reported Risky Driving Score results as risk reduction percentages in the abstract risks giving people an exaggerated impression of effectiveness. The range of possible score isn't very wide, so even a small difference can be a substantial percentage. It would have been good if more details about the score were provided, given that it's a primary outcome measure and it was a trial-specific adaptation of an existing score.

It's great to see this trial published, even though it didn't meet its goals. But I don't agree with the authors' conclusion that statistical significance levels should be dropped low, in effect, because proven interventions are needed. The interventions that people would use need to make a real difference. As the authors point out, there is evidence that parents can make a difference to their adolescents' behaviors - to their list, I'd add influencing smoking (Thomas RE, 2007). But parents need to know where they could make the best effort, given the other options like Parent-Teen Driving Agreements (Zakrajsek JS, 2013) - or discouraging getting a license early (Ian R, 2001).

The authors indicate that future research will integrate more objective data, which presumably refers to the unreported data from 2010 for driving citations and crashes in this trial. That will be vital to put this self-reported data on surrogate outcomes in perspective. Access for others to the intervention materials may be important for others in the field (Glasziou P, 2010).