Originally Posted by
PhilipK
But the overall end-to-end risk is the same in both cases, and as the actual conversation is the same the only point of difference is the physical set-up/holding/shut-down. If this was materially more distracting/dangerous than handsfree, then the evidence would have shown a corresponding greater number of collisions. But it doesn't - hence the logical deduction from the evidence is that there is no material (statistically significant) difference.
That's utterly spurious, and shows a real lack of understanding of how scientific method works. You can always find outliers (my cars allow me to dial a call, digit by digit, using a touch screen in the centre console - but that's classed as handsfree!), so you need to have a large enough data set to get an overall average.
Of course rooting around in a bag in the footwell to find a phone is more dangerous than an "average" call, just as typing in the digits on the screen would be. But when you compare 10,000 or 100,000 or whatever handheld and handsfree calls, then these extremes don't influence the overall result.