9 ms·

Car passengers rarely wear helmets, but don't most paddlers wear life jackets? When I see people out on the river they're almost always wearing them.

by jefftk 4y ago

robryk 4y ago
This is exactly my point. Without knowing how common {wearing helmets in cars, wearing PFDs in kayaks} is, the statements imply nothing about safety benefits of either, and yet that one was presented in a way that suggests that it does. What would be a non-misleading value to quote would be absolute change of risk of drowning (e.g. that a typical trip without a PFD costs X micromorts, while a typical trip with one Y micromorts). What would be less problematic (but still potentially misleading[1]) would be a relative risk reduction (wearing PFD makes you X times less likely to die). [1] Because it doesn't tell you anything about the original risk that you're lowering. E.g. helmets are a good protection against falling bricks: equally good at construction sites as when you're walking down the street. The only difference is that falling bricks are more likely on a construction site.
- bananasbandanas 4y ago
  While it's shoddy statistics, at least in this case the implied effect seems to be real. According to these two sources [1][2] that just came up when I searched for this, prevalence of wearing life-jackets among kayakers appears to be ~78%. [1] https://injuryprevention.bmj.com/content/4/3/203 https://injuryprevention.bmj.com/content/4/3/203 [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5931488/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5931488/
  - robryk 4y ago
    I have very little doubt the effect's real. Note though that getting base rates from one place and getting rates of accidents from another is usually a bad idea: they will have various ways of measuring the rates, so will have different biases (based on location, time-of-day, time-of-year, ... where the measurement happens).
pvaldes 4y ago
> don't most paddlers wear life jackets? It depends on the area, difficulty level and water temperature. Life jackets have pros and cons. Can be an obstacle when swimming after a drifting kayak or even worse rescuing somebody that fell in the water. A jacket will also block you to get impulse to return to the kayak in some cases (because you are unable to submerge). I often don't wear one but the children must wear it. Of course in the sea the idea of not wearing a jacket is out of the discussion

Car passengers rarely wear helmets, but don't most paddlers wear life jackets? When I see people out on the river they're almost always wearing them.

by jefftk 4y ago

Car passengers rarely wear helmets, but don't most paddlers wear life jackets? When I see people out on the river they're almost always wearing them.

robryk 4y ago

This is exactly my point. Without knowing how common {wearing helmets in cars, wearing PFDs in kayaks} is, the statements imply nothing about safety benefits of either, and yet that one was presented in a way that suggests that it does. What would be a non-misleading value to quote would be absolute change of risk of drowning (e.g. that a typical trip without a PFD costs X micromorts, while a typical trip with one Y micromorts). What would be less problematic (but still potentially misleading[1]) would be a relative risk reduction (wearing PFD makes you X times less likely to die). [1] Because it doesn't tell you anything about the original risk that you're lowering. E.g. helmets are a good protection against falling bricks: equally good at construction sites as when you're walking down the street. The only difference is that falling bricks are more likely on a construction site.

bananasbandanas 4y ago
While it's shoddy statistics, at least in this case the implied effect seems to be real. According to these two sources [1][2] that just came up when I searched for this, prevalence of wearing life-jackets among kayakers appears to be ~78%. [1] https://injuryprevention.bmj.com/content/4/3/203 https://injuryprevention.bmj.com/content/4/3/203 [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5931488/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5931488/
- robryk 4y ago
  I have very little doubt the effect's real. Note though that getting base rates from one place and getting rates of accidents from another is usually a bad idea: they will have various ways of measuring the rates, so will have different biases (based on location, time-of-day, time-of-year, ... where the measurement happens).

pvaldes 4y ago

> don't most paddlers wear life jackets? It depends on the area, difficulty level and water temperature. Life jackets have pros and cons. Can be an obstacle when swimming after a drifting kayak or even worse rescuing somebody that fell in the water. A jacket will also block you to get impulse to return to the kayak in some cases (because you are unable to submerge). I often don't wear one but the children must wear it. Of course in the sea the idea of not wearing a jacket is out of the discussion