Originally Posted by kthutchinson
I find VT's use of odds ratio analysis somewhat troubling, as it can give a very skewed answer... Using the odds ratio gives a much more alarming answer than using the probability ratio.
As Mark Twain used to say (attributing it to British Prime Minister Benjamin Disraeli)
"There are three kinds of lies: lies, damned lies, and statistics." One has to be extremely careful, detailed and scientific when manipulating and trying to understand what a series of events actually represents, and if the sample size is under 1,000 with no control group (not that you could have one for this), lumping dropping your bike at virtual stand-still in with running off the road, etc.,and with the virtually unlimited variables, it makes the problems insurmountable in my mind.

To further invalidate the study all you need to do is read it and see what they are counting! A full 37.8% of all their CNC (Crash or Near-Crash) events are identified as
Subject over left/right lane line Negotiating a curve
Naturally the vast majority of these were "Subject over left lane line" as far too many people cut their corners. Cutting a corner, however, especially if there is a clear line of sight with no oncoming traffic, while inappropriate, is a far cry from what should in a rational world be considered a CNC incident.

As I mentioned, earlier, there is an outlier here that completely skews the results of this study to the point of not being able to have useful statistics. One can draw useful information, but definitely not statistics.

One individual rider (1% of the group) accounted for 13 CNC incidents (8.5%). Without knowing what these were, it's really impossible to the meaning of these figures. If they rode on isolated open roads and had poor lane discipline when there wasn't any traffic, than that is an issue but not a "Near-Crash" incident in my book.

Watch the video on page 14 of the PDF under the "Crash Descriptions" headline. Rider comes up to a stop sign to turn right. At a virtual stop the rider drops the bike. It is not a crash nor is it a near-crash. It is a drop and I strongly feel it has no business being included in the CNC portion of the study. Certainly it can be used to identify that some of us have poor control of our bikes and virtually all of us will have a brain-fade and drop a bike (I've done it a couple of times), but do not lump that into a CNC statistic.

57% of the 30 crashes were low-speed “capsizes”
Which that video is listed as an example of.

The real problem here is that the sample size is absolutely way too small to build any credible statistics on and including things like a simple bike drop at 0.5 mph or cutting a corner on a wide-open full view deserted road are considered to be CNC incidents.

There is good info to be gleaned but, there are also, for me, significant issues which make me scratch my head.