Relating personal experience - Isn't it strange ...

[rmurphy195]

Isn't it strange that when relating personal experience, or events that I've witnessed myself in regards to helmets, there's always someone, somewhere who tries to convince me that it can't be so?

Why is that, can anyone say?

[irc]

I've no idea. It would depend on what you said. In general though people often draw conclusions from personal experience that are wrong. For example "my helmet saved my life." There are so many of these stories about that there should be carnage amongst unhelmeted riders but there isn't.

it's not a simple matter to draw conclusions about the benefit a broken or deformed helmet might have provided in a crash. However, the fact that serious injury to unhelmeted cyclists is as rare as helmet damage is common, suggests that most of the claims of benefit from damaged helmets are likely to be exaggerated.i

http://www.cyclehelmets.org/1209.html

Helmets should be a matter of personal choice but some people and some organisations distort facts, exaggerate, and draw debatable or just pure wrong conclusions from indivual incidents. Unless the propoganda is countered we might end up with a helmet law.

[PH]

Not knowing specifically what it is you refer to - You'd have to experience or witness the same event with all it's combinations and different outcomes to reach any conclusion that wasn't just conjecture. That two people have reached different conclusions from their different experiences isn't strange at all.

[kwackers]

Isn't it strange that when relating personal experience, or events that I've witnessed myself in regards to helmets, there's always someone, somewhere who tries to convince me that it can't be so?

Why is that, can anyone say?

Personal experience is the worst form of data to base anything on.
Realising the types of bias and how we apply them is interesting and a bit of an eye opener. Once you get past it then you can look at real world data and the truth behind it.

I started out thinking "helmets must work!" and tried to prove it...

[Bicycler]

Are people disputing what you saw or how you've interpreted what you saw? "I saw a helmeted rider bang his head and he was not seriously hurt" is what you might have observed and it is unlikely that somebody will challenge that. Comments like "the helmet saved his life" or "he would have been injured without a helmet" are conjecture rather than observation and open to challenge. You might rate your ability to draw these conclusions quite highly. The problem is that everybody thinks themselves a good judge, and yet the claims for lives saved by helmet always vastly exceed the number of cases for which it could actually be true even if helmets prevented every single helmeted head injury (which we can say with certainly that they don't). It turns out that people are very poor estimators of "what would've happened if".

[[XAP]Bob]

Isn't it strange that when relating personal experience, or events that I've witnessed myself in regards to helmets, there's always someone, somewhere who tries to convince me that it can't be so?

Why is that, can anyone say?

Events, you're the witness - the conclusions we draw are often suspect.

If the event was 'cyclist hit head' there is no argument.
If the event was cyclists' lives saved by helmet in shop window - well, we might well question the conclusion.

[Mick F]

Personal experience is the worst form of data to base anything on.

That is a statement that is open to a good long debate!

I'll take the floor first ................

Personal experience is the only experience that we can judge anything upon. Other people's experiences may be at odds with mine, but it doesn't mean my experience is invalid, and if you were to ask a hundred people and they all agreed with me, it doesn't mean that your experience is invalid either.

Therefore, no experiences are valid, and therefore no data is valid because it doesn't fit with personal experiences.

[kwackers]

Personal experience is the only experience that we can judge anything upon. Other people's experiences may be at odds with mine, but it doesn't mean my experience is invalid, and if you were to ask a hundred people and they all agreed with me, it doesn't mean that your experience is invalid either.

Therefore, no experiences are valid, and therefore no data is valid because it doesn't fit with personal experiences.

What I'm trying to say (badly) is that anecdotes prove nothing. You might think you saw/felt/heard/experienced something but your experience is highly subjective and prone to cognitive bias.
Which in this context means you cant realistically draw the conclusion that helmets save lives just because you saw someone survive falling off a bike with one.

What we can do though is use statistical methods in some instances to show that such experiences must be false.
In the case of helmets this is easy, the number of people who've witnessed a life being saved by a helmet is huge. Therefore obviously anyone riding without one stands a high chance of dying and since the numbers don't show this...

[Bicycler]

Personal experience is the only experience that we can judge anything upon. Other people's experiences may be at odds with mine, but it doesn't mean my experience is invalid, and if you were to ask a hundred people and they all agreed with me, it doesn't mean that your experience is invalid either.

Actually Mick I think you've just supported Kwackers' argument.

In the absence of other data we might have to rely on personal experience. In personal matters such as "which saddle is most comfortable" then it might be the best or only source of information. Where we are discussing facts on contentious matters, subjective conclusions drawn from individual observations are not a very good form of data.

[[XAP]Bob]

Personal experience is the only experience that we can judge anything upon. Other people's experiences may be at odds with mine, but it doesn't mean my experience is invalid, and if you were to ask a hundred people and they all agreed with me, it doesn't mean that your experience is invalid either.

Therefore, no experiences are valid, and therefore no data is valid because it doesn't fit with personal experiences.

What I'm trying to say (badly) is that anecdotes prove nothing. You might think you saw/felt/heard/experienced something but your experience is highly subjective and prone to cognitive bias.
Which in this context means you cant realistically draw the conclusion that helmets save lives just because you saw someone survive falling off a bike with one.

What we can do though is use statistical methods in some instances that such experiences must be false.
In the case of helmets this is easy, the number of people who've witnessed a life being saved by a helmet is huge. Therefore obviously anyone riding without one stands a high chance of dying and since the numbers don't show this...

It doesn't, of course, show that all such observations are false, but it does indicate that either there is something about wearing helmets that means wearers need their lives saved a whole lot more than non wearers - or that the vast majority of 'saved a life' claims are not actually true (leaving room for the statistical outlier where the hat may indeed have saved a life, somewhere, somewhen)

[Mick F]

............ Where we are discussing facts on contentious matters, subjective conclusions drawn from individual observations are not a very good form of data.

Facts?
Truth?

What is truth?

[horizon]

Isn't it strange that when relating personal experience, or events that I've witnessed myself in regards to helmets, there's always someone, somewhere who tries to convince me that it can't be so?

Why is that, can anyone say?

I raised this point over two years ago here:

viewtopic.php?f=41&t=79708

Helmets are very strange things in relation to personal experience versus statistics and it's hard to find similar things to compare them to in this regard.

[irc]

As Ben Goldsmith said in the BMJ

the current uncertainty about any benefit from helmet wearing or promotion is unlikely to be substantially reduced by further research. Equally, we can be certain that helmets will continue to be debated, and at length.

http://www.bmj.com/content/346/bmj.f381 ... eytype=ref

[Steady rider]

There is some evidence that helmet use increases both the accident rate and head/helmet impact rate, so that wearers will report extra impacts compared with non-wearers. The experience of wearers will tend to report broken helmets with them not being overly robust. Many may take the outcomes as evidence that they provide a safety benefit. This assumed safety benefit may be off set by the increased number of accident and by more head impacts. http://www.dailymail.co.uk/sciencetech/ ... ident.html

The case against bicycle helmets and legislation
http://www.ta.org.br/site/Banco/7manuai ... helmet.pdf
The above report provides some guide to the positive and negative aspects.

Individuals who wear helmets reporting their own experiences may be convinced that a benefit has occurred because they are judging potentially be the extra impacts and damaged helmets but this does not relate to the fuller picture including the accident rate and extra impacts. It is near impossible for individual experiences of helmet wearers to form a balanced view.

[rfryer]

Isn't it strange that when relating personal experience, or events that I've witnessed myself in regards to helmets, there's always someone, somewhere who tries to convince me that it can't be so?

Why is that, can anyone say?

It's because some people are very concerned about helmets becoming compulsory, and react strongly (too strongly, in my opinion) to counter any positivity about them.

My view is that I'd rather have a less polarised debate on the subject. My take on it is that there are various sources of information that can be taken into account when making a decision about helment wearing, and it's useful to share information about them, rather than rubbishing those sources that you feel don't fit your campaign. I'd break them down as:

• Common sense, reason Thinking about why a helmet can have positive, or negative effects on safety.
  
• Personal experience, & anecdotal evidence from others Especially when they confirm, or refute, common sense arguments. For example, I've see a lot of "helmet saved my life" claims, but not very many "helmet nearly killed me" claims.
• Knowledge of local cycling conditions, and personal cycling style This is critical; the effect on your safety of wearing a helmet depends very much on where you cycle, what you cycle, and the balance of risks in the way you ride. The answer will vary for different people, and even for an individual at different times.
• Expectations Would you consider wearing a helmet purely to increase your chance of surviving a major trauma? Or is it worth wearing simply to reduce the chance of cuts and grazes?
• Statistics This is where I disagree with a lot of forummers; I'm not prepared to put much weight on statistical evidence, for two fundamental reasons. Firstly, I don't believe the statistics out there are based on complete data - for example, I have had a number of falls, with and without a helmet, and none of them are tracked in any statistics. Secondly, even if they were entirely trustworthy, and said with authority "on average, safety (both in terms of death, and injuries of all severities) is reduced (or increased) by 5% by wearing a helmet", how would that help me in deciding whether to wear one tonight, on my very specific, completely non-average ride?

In conclusion - I think that the decision whether or not to wear a helmet should be a considered one, and people that try to shut down debate from either side aren't helping those of us that are interested in collecting the evidence to make the decision that's right for us.