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#1371
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"Just zis Guy, you know?" writes:
On Mon, 07 Feb 2005 06:18:30 GMT, (Bill Z.) wrote: Unfortunately, these guys have been arguing that helmets do not reduce head injuries for years. Really? Where? If you look at real-world figures they have no measurable effect on serious and fatal head injuries, but I don't know anybody who says they don't prevent the trivial cuts and bumps they are designed for. Sigh. "Where" is on this newsgroup. It is obvious that you are trolling, bringing up the discredited "fatality" nonsense yet again (fatalities are so few in numbers that attempts to use them to evaluate helmets usually lead to null results due to statistical noise.) I'll skip the rest of your missives today - you are just trying to bring up yet another strawman (and a previously discredited one at that.) -- My real name backwards: nemuaZ lliB |
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#1372
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#1374
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b_baka wrote:
The answer would have to be that they reduced head injury but the overall effect might be to make cyclists braver than they should be whilst wearing a minimal helmet. Actually, we've seen the opposite assertion here from the anti-helmet people. They claim that the reason (or part of the reason) why the injury and fatality rates are statistically lower for helmet wearers, is not because of any protection the helmet offers, but because helmet wearers are also more cautious riders. Not sure which, if any, of these arguments is true. I can see both possibilities. Along those lines I would add that if the crash is bad enough to damage other parts of the body beyond repair, survival might not be desirable. We're really talking about head impacts here, not being crushed by a vehicle. I don't know what the stats are on how many people ended up living due to a helmet, but were in such a state that they would have rather not survived. Too morbid. As an adult the choice of whether or not to use a helmet should be mine. And that's why I'm against MHLs, but while at the same time being adult enough to admit that wearing a helmet does have its benefits. |
#1375
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Steven M. Scharf wrote:
b_baka wrote: The answer would have to be that they reduced head injury but the overall effect might be to make cyclists braver than they should be whilst wearing a minimal helmet. Actually, we've seen the opposite assertion here from the anti-helmet people. They claim that the reason (or part of the reason) why the injury and fatality rates are statistically lower for helmet wearers, is not because of any protection the helmet offers, but because helmet wearers are also more cautious riders. Not sure which, if any, of these arguments is true. I can see both possibilities. Along those lines I would add that if the crash is bad enough to damage other parts of the body beyond repair, survival might not be desirable. We're really talking about head impacts here, not being crushed by a vehicle. I don't know what the stats are on how many people ended up living due to a helmet, but were in such a state that they would have rather not survived. Too morbid. As an adult the choice of whether or not to use a helmet should be mine. And that's why I'm against MHLs, but while at the same time being adult enough to admit that wearing a helmet does have its benefits. No argument from me, but I do remember one cyclist crashing in the TdF last year and it was caught on tape, where he went off the bike and hit the back of his head rather hard. That is exactly the part of the head that a bicycle helmet should protect since a hard enough impact there could be fatal. All from me, Bill Baka |
#1376
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"Steven M. Scharf" wrote in message k.net... b_baka wrote: The answer would have to be that they reduced head injury but the overall effect might be to make cyclists braver than they should be whilst wearing a minimal helmet. Actually, we've seen the opposite assertion here from the anti-helmet people. They claim that the reason (or part of the reason) why the injury and fatality rates are statistically lower for helmet wearers, is not because of any protection the helmet offers, but because helmet wearers are also more cautious riders. No, only that *voluntary* helmet wearers (i.e. those who freely chose to do so in the absense of a MHL or other intensive social pressure) tend to be more cautious riders. The whole point about risk compensation theory is that coercing people into using safety equipment that they otherwise wouldn't chose to use on their own initiative is likely to cause them (at least at the subconscious level) to take more risks than they otherwise would have if they weren't using that safety equipment. Something similar may be happening with voluntary helmet wearers as well, but unless the elicited increase in risky behaviour is greater than their inborn aversion to taking such risks in the first place, it is doubtful we would ever see much of an effect in the overall stats for that particular segment of the population. For seat belt use, the only real risks appear to be transfered to bicyclists, pedestrians, and the unbelted passengers of drivers who otherwise wouldn't use seat belts. For bicycle and motorcycle helmet use though, the additional risks taken by riders who otherwise wouldn't chose to wear a helmet appear to equal or exceed the actual safety benefit to be derived from the use of such equipment, which is why we see so little evidence of a net safety benefit at the whole population level (other than that associated with depressing the total number of bicyclists or motorcyclists of course). Riley Geary |
#1377
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"John_Kane" wrote in message oups.com... Can I get a cite on the Utah study ? It looks interesting The relevant data is from Table 51 of NHTSA's State Data System Crash Data Report: 1990-1999, which can be found at http://www-nrd.nhtsa.dot.gov/pdf/nrd.../15safetyequip Utah is one of 17 states contributing data to the SDS, which is a database similar to FARS, except that it includes *all* injury-related traffic crashes, not just those resulting in a fatality. There is a considerable problem with the Utah MC helmet data, in that for about 72% of both the fatal and non-fatal cases from 1990-99, helmet use status is listed as "unknown." Nonetheless, if the remaining 28% of the cases where helmet use status is known are actually representative, we have 43 helmeted fatalities, 5 non-helmeted fatalities, 1561 helmeted non-fatalities, and 185 non-helmeted non-fatalities, which yields an apparent odds ratio of (43/5)*(185/1561) = 1.02 -- or essentially a null effect (i.e. helmeted motorcyclists being about equally likely to suffer a fatal injury relative to non-helmeted motorcyclists). OTOH, because of the low number of fatalities involved, the result is exceedingly unstable. For example, changing just a single "Helmet use unknown" fatality to a "Helmet not used" fatality reduces the apparent odds ratio to 0.85 (a 15% net safety benefit), so these results should be treated with considerable caution. Riley Geary |
#1378
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wrote in message oups.com... Riley Geary wrote: Year Reg MC Fatalities/10,000 Reg MC (NCSA) 1993 38000 7.6 1994 36000 7.8 1995 36000 7.8 1996 36000 7.8 1997 37000 5.4 1998 37000 9.5 1999 39000 9.7 2000 43000 9.3 2001 48000 11.8 2002 51000 12.9 2003 54000 12.6 The other problem here is that the LA-DPS data conveniently begins with 1997, a year with an anomalously low number of motorcycle fatalities in Louisiana. Was this simply an innocent choice of both the data range and data source by the author of section V, or was it deliberately chosen to mischaracterize the increase in motorcycle fatalities per 10,000 registered motorcycles as being much higher than it really was following repeal of Louisiana's MHL? It was both innocent and deliberate. Oh really? The more I dig into the "Evaluation of the Repeal of Motorcycle Helmet Laws in Kentucky and Louisiana" report at http://www.nhtsa.dot.gov/people/inju.../kentuky-la03/ the more fraudulent the whole study appears to be, so I'll have to eventually provide a more comprehensive critique of it; but first... It was the year before the repeal, versus the year of the repeal. Totally logical. But if you want to average 1993-1997, then average 1998-2003, that's fine too. And why would we want to do that when the MHL wasn't repealed until August, 1999? The 1998 data must be included on the other side of the ledger, and the 1999 data should probably not be a part of either data set since it was a transitional year. Now this obviously won't change the fact that motorcycle fatality rates have indeed risen much faster in Louisiana than in most other states recently, but your evident inability to get even the simplest things straight is becoming increasingly annoying. Do we really need to fact-check every piece of data you wish to bring to our attention? 7.3 per 10K with MHL versus 11.0 per 10K after the repeal. So it's only a 51% increase in fatalities. And again, it's the fatality *rate* per 10K registered motorcycles we're talking about here, not fatalities. But the real point (assuming there really is a point, given the natural variation inherent in the statistics of small numbers) is that the fatality rate didn't suddenly jump as a response to the repeal of the MHL, but had already been on the upswing for the year-and-a-half prior to repeal, and actuall *fell* during the first full year following repeal! Well, that last part isn't quite true either. It turns out NHTSA has not been consistent in the presentation of its motorcycle fatality rate per 10K registered motorcycles data. Starting with the 1996 Fact Sheet, it began calculating the fatality rate based on registration data from the previous year rather than the current year, with the further complication that the 1998 Fact Sheet erroneously repeated 1996 registration data instead of using the 1997 numbers, and the 2000, 2001, and 2003 Fact Sheets apparently used both previous year fatalities and registrations. Sorting through all this obfuscation, and assuming for the moment that 1996 and 1997 registration numbers are essentially equivalent (which certainly seems to be true for Louisiana at least), we have the following corrected fatality rates for Louisiana: Year Reg MC Fatalities/10,000 Reg MC (NCSA) 1993 38000 7.6 1994 36000 7.8 1995 36000 7.8 1996 37000 7.6 1997 37000? 5.4 1998 39000 9.0 1999 43000 8.8 2000 48000 11.9 2001 51000 12.4 2002 54000 12.2 Sorry Riley. There is just no way you can twist the data to prove what you're trying to prove. No, I'm the one trying to untwist the data so you can actually understand it, but I suspect that may be a rather hopeless cause by this point. And it doesn't matter anyway. The states did the right thing by repealing the MHLs, but don't kid yourself into thinking that they did it without knowing that there'd be consequences in the fatality rates. Sure there are likely to be consequences in terms of increased fatalities whenever a MHL is repealed, but that's primarily due to the increase in motorcycling by aging boomers such a repeal facilitates, not to any real change in the underlying fatality rate with respect to either registrations or vehicle miles travelled. As a little sneak preview of my forthcoming critique on the Kentucky/Louisiana study, I'll simply point out that Louisiana is the *only one* of the five states repealing their MHL's to see a significant long-term increase in fatality rates for motorcyclists thus far. It could be argued that Kentucky (1998) and Texas (1997) still have marginally higher fatality rates than they had in the last few years prior to repeal, at least as of 2002, but Florida (2000) has been essentially flat, and Arkansas (1997) actually has a substantially *lower* fatality rate now than it had prior to repeal. Likewise, Guy had earlier posted CDC data indicating states without a MHL generally had lower fatality rates than states with a MHL, and my recent research into the subject comfirms that finding--with the 25 continuously non-MHL states experiencing a slight decline over the past decade (from about 5.3 to 5.0) and the 20 continuously MHL states (plus DC) experiencing a more pronounced increase since the mid-to-late-1990's (from about 5.5 to 6.5), so who is really kidding whom about fatality rates? Riley Geary |
#1379
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Riley Geary wrote: Likewise, Guy had earlier posted CDC data indicating states without a MHL generally had lower fatality rates than states with a MHL, and my recent research into the subject comfirms that finding--with the 25 continuously non-MHL states experiencing a slight decline over the past decade (from about 5.3 to 5.0) and the 20 continuously MHL states (plus DC) experiencing a more pronounced increase since the mid-to-late-1990's (from about 5.5 to 6.5), so who is really kidding whom about fatality rates? Riley's dedication and perception in analyzing data are well known, and have been the subject of at least one article in a national cycling magazine. I'll note, though, that some readers may not have the desire to follow his detailed numerical analyses. For those readers, the following article covers some of the same territory as Riley's paragraph above: http://www.forbes.com/fyi/99/0503/041.htm |
#1380
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On Tue, 08 Feb 2005 17:27:46 GMT, "Steven M. Scharf"
wrote: The answer would have to be that they reduced head injury but the overall effect might be to make cyclists braver than they should be whilst wearing a minimal helmet. Actually, we've seen the opposite assertion here from the anti-helmet people. They claim that the reason (or part of the reason) why the injury and fatality rates are statistically lower for helmet wearers, is not because of any protection the helmet offers, but because helmet wearers are also more cautious riders. Actually both, as noted by Mok, et. al, and by others. Spaite notes that helmet users are less likely to crash in the first place, while Rodgers finds that they have a significantly higher death rate when they do crash. And who are these "anti-helmet people"? Names. Not sure which, if any, of these arguments is true. I can see both possibilities. Both are true. Along those lines I would add that if the crash is bad enough to damage other parts of the body beyond repair, survival might not be desirable. We're really talking about head impacts here, not being crushed by a vehicle. I don't know what the stats are on how many people ended up living due to a helmet, but were in such a state that they would have rather not survived. Too morbid. Logical fallacy: appeal to fear. One key fact is that when a number of cyclist fatalities, with cause of death recorded as head injury, were analysed in detail, it was found that the majority also had other injuries which would have been fatal. As an adult the choice of whether or not to use a helmet should be mine. And that's why I'm against MHLs, but while at the same time being adult enough to admit that wearing a helmet does have its benefits. And stupid enough to deny that it may have disbenefits, despite the evidence to that effect. Logical fallacy: slothful induction. Guy -- May contain traces of irony. Contents liable to settle after posting. http://www.chapmancentral.co.uk 88% of helmet statistics are made up, 65% of them at CHS, Puget Sound |
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