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Study claims US cities with share programs see greater proportion of head injuries among all bike-related injuries - but the number of head injures went down

American cities with bike sharing programmes similar to London’s Barclays Cycle Hire Scheme have seen an increase in head injuries as a proportion of bicycle-related injuries, according to a controversial new study. However, another researcher has pointed out that the actual numbers of head injuries in those cities went down.

Research from the University of Washington and Washington State University found that the risk that a bicycle-related injury involved a head injury increased 14 percent after bike-share schemes were begun in several major cities.

Of all bicycle-related injuries that occurred in bike-share cities (Boston, Miami Beach, Minneapolis, Washington, D.C., and Montreal, Quebec) during the study period, the proportion that were head injuries rose from 42 percent to 50 percent after bike-share program implementation. No such increase was found in cities without these programs.

Although the trauma-registry data for bicycle-related injuries for two years before and one year after bike programs began saw an increase in head injuries, it was not proven that these injuries occurred on a hire bike.

“Our results suggest that bike-share programs should place greater importance on providing helmets so riders can reap the health benefits of cycling without putting themselves at greater risk for injury,” said the research lead, Janessa Graves. 

In September, Seattle will be one of the first cities in the USA to offer helmet hire along with bikes. Helmets will cost $2 per day - a move that is forced by a local mandatory helmet law.
 
“It doesn’t take much effort to wear a helmet when you bike,” Graves said, “but doing so could make all the difference.”
 
But in the following days scorn was poured on the research by Kay Teschke, who studies city cycling at the University of British Columbia.

"When I actually looked at the data, I thought, oh my goodness, the injuries actually went down," she told CityLab. "In the bike-share cities, the total number of injuries went down, and the number of head injuries went down."

The article went on to point out that:

Graves and team reported that the proportion of head injuries as a share of total injuries increased in the bike-share cities after the programs began, going from roughly 42 percent to 50 percent.

Meanwhile, the proportion of head injuries to total injuries stayed statistically flat in the non-bike-share control cities, going from roughly 38 percent to 36 percent. 

From that, the researchers concluded that bike-share "is associated with increased odds that a person admitted for a bicycling-related injury would have a head injury." 

That's a very nuanced finding, with the key word in the report being proportion. It wasn't that head injuries increased in bike-share cities. It was that head injuries as a proportion of total injuries increased in bike-share cities, particularly in comparison with non-bike-share control cities.

"It seems critical to me, especially for people interested in bike-share, to report that injuries overall went down, including head injuries," says Teschke.

"That's really important. Especially because it is likely that cycling went up in those cities."

After an unpromising start, having to be bribed by her parents to learn to ride without stabilisers, Sarah became rather keener on cycling in her university years, and was eventually persuaded to upgrade to proper road cycling by the prospect of a shiny red Italian bike, which she promptly destroyed by trapping a pair of knickers in the rear derailleur. Sarah writes about about cycling every weekend on road.cc.

6 comments

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levermonkey [669 posts] 2 years ago
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"Lies, Damn Lies and Statistics" - Duke of Wellington

Statistics will always show exactly what you want them to show. Take a recent item in Road.CC News

1 in 3 think over 40s should not wear Lycra.
The majority of people think it's Ok to wear Lycra over 40.

Same figures, different slant.

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FluffyKittenofT... [1239 posts] 2 years ago
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- deleted in a desperate attempt to stop arguing about helmets -

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bikebot [2010 posts] 2 years ago
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levermonkey wrote:

"Lies, Damn Lies and Statistics" - Duke of Wellington

Statistics will always show exactly what you want them to show. Take a recent item in Road.CC News

1 in 3 think over 40s should not wear Lycra.
The majority of people think it's Ok to wear Lycra over 40.

Same figures, different slant.

I hate that quote. Statistics are impartial, interpretation varies.

Never trust the headline, go to the source and see the data.

Avatar
levermonkey [669 posts] 2 years ago
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Statistics are never impartial because a human pays for the survey, a human asks the questions, a human does the analysis of the answers and a human publishes the answers.

Humans are biased. Humans are shaped by their culture and their upbringing so no statistics are unbiased.

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bikebot [2010 posts] 2 years ago
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Sorry, bad wording.

Data is impartial. If it's collected badly, or processed badly then it's wrong, and the blame lies with the researcher or the method.

Where I think we have a growing problem is with a large chunk of society that just rejects data, full stop, and instead wants to rely on something they usually call "common sense". Which basically means whatever the hell they think is right without doing any research at all.

Why I have a problem with that now heavily overused saying, is that it implies that using statistics, data or research is the mistake, rather than the corruption of it by particular parties. That actually lends authority directly to the vested interest.

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jmaccelari [243 posts] 2 years ago
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It wouldn't surprise me.

The usage of hire bike by people not used to riding bikes is (one would assume) much higher than the use of bikes by people who own bikes. So one would assume the propensity to come off is greater amongst a sampling of hire-bike cyclists.

I would also assume the ownership and usage of cycling equipment (especially) helmets is MUCH lower in this group as well. Cycling helmets (I believe) do have a beneficial effect in 'falling off' type accidents (from personal experience), so I would assume that there may be more head injuries due to more crashes...

Sounds reasonable, but not worth a headline...