Great video on the "normalization of deviance" error

[Omisson]

So, this sort of behavior in cave divers, tec divers, explains much of the incidents we see in statistics, there will always be "undeserved hits" but this sums up the short cut thinking that belies most diving accidents.


Keynote Speaker: Mike Mullane

 

[scagrotto]

Normalization of deviance is just one aspect of complacency.

Here's a simple fact that everybody knows, but may not have given much thought. Every single person who ever died in a fatal accident died in their first fatal accident. It's obvious that not having already died doesn't mean we can't die next time, but I think we almost all inflate the significance of our past success when we consider our chances of future failure. If you've done something successfully 999 times you may have a failure rate of 0.1% or less, but that doesn't necessarily mean your chances of failure are less than 0.1%. Sometimes you're just one more small error away from connecting all the necessary dots.

 

[BRT]

The first fatal accident is the last but often there are a bunch of close calls before it if we are paying attention. We aften are not too surprised when we lose an aquaintance in a car accident. We know something about their driving practices. And they probably knew more if they had paid attention.

 

[mick allein III]

The learning mechanism behind what Mike Mullane describes is called negative reinforcement. A behavior (taking a safety short cut) is maintained or increased by the avoidance of an aversive consequence. I see the all the time at dive sites recreational and technical. Divers need to create a culture of safety where individual divers are expected to and acknowledged for safe behavior. A diver should be supported for calling a dive, diving within their comfort zone, staying close to a team member, etc.


Sent from my iPhone using Tapatalk

 

[Jan Kruger]

Divers need to create a culture of safety where individual divers are expected to and acknowledged for safe behavior. A diver should be supported for calling a dive, diving within their comfort zone, staying close to a team member, etc.

I totally agree that a safe diver should be supported. It saves lives. Other divers learn from that. Diving and safety standards should be kept at a high level...especially in the company of new divers.

 

[rx7diver]

So, this sort of behavior in cave divers, tec divers, explains much of the incidents we see in statistics, there will always be "undeserved hits" but this sums up the short cut thinking that belies most diving accidents.


Keynote Speaker: Mike Mullane

I agree with Mullane's thesis: "Normalization of deviance" leads to increased risk. I don't completely agree with his example. Not completely. My understanding is, Challenger's last flight occurred on a day that started off much, much colder than with any previous space shuttle flights'. These very cold temperatures compromised the ability of the booster rocket O-rings to quickly and sufficiently seal the rockets' joints when pressure built up inside the booster rockets, which led to the breaches and the catastrophe. It was the unprecedented, excessively cold temperature that is believed to have been the direct cause of the catastrophe.

If Challenger had flown, instead, again and again at this very cold temperature, with the catastrophe eventually "catching up" with NASA, then Mullane's using the Challenger catastrophe as an example would make more sense (to me).

Physicist (Nobel laureate) Richard Feynman's book ("Surely You're Joking ...") is worth reading regarding all this.

(A chapter of my 1991 statistics PhD dissertation pertains to this disaster. Specifically, a Bayesian statistical approach is employed to show that the likelihood of booster rocket O-ring failure increases dramatically with decreasing start temperature.)

Safe Diving,

rx7diver

 

[Bob DBF]

Basically, if you are taking a calculated risk, calculate it properly.



Bob
-----------------------------
I think that advocating unsafe and dangerous practices is both stupid and foolish. That is why I don't tell people to do what I do. Dsix36

 

[eponym]

The biggest impact I've had on this sort of behavior (in myself and in others) is based on Steve Lewis quoting Wayland Rhys Morgan as follows:

Next time you intend to deviate from best practice, take a piece of note paper and divide it into two columns. Write in block letters at the top of the left-hand column, "What people usually do." On the right (also in block letters) write, "What I am going to do instead." Then in the appropriate column complete a brief explanation of each behavior in clear, concise language. Read it back to yourself, sign and date it, then give it for safekeeping to someone you trust--lover, spouse, son, daughter, best buddy, favorite cowgirl, it really does not matter much, just hand it over. Tell them to give it to whomever it is that leads the inquiry should something bad happen to you.

 

[scuba5150]

I agree with Mullane's thesis: "Normalization of deviance" leads to increased risk. I don't completely agree with his example. Not completely. My understanding is, Challenger's last flight occurred on a day that started off much, much colder than with any previous space shuttle flights'. These very cold temperatures compromised the ability of the booster rocket O-rings to quickly and sufficiently seal the rockets' joints when pressure built up inside the booster rockets, which led to the breaches and the catastrophe.

If Challenger had flown, instead, again and again at this very cold temperature, with the catastrophe eventually "catching up" with NASA, then Mullane's using the Challenger catastrophe as an example would make more sense (to me).

Physicist (Nobel laureate) Richard Feynman's book ("Surely You're Joking ...") is worth reading regarding all this.

(A chapter of my 1991 statistics PhD dissertation pertains to this disaster. Specifically, a Bayesian statistical approach is employed to show that the likelihood of booster rocket O-ring failure increases dramatically with decreasing start temperature.)

Safe Diving,

rx7diver

As reported in Feynman's Appendix A to the Roger's Commission report on the Challenger loss, the possibility of such a catastrophic accident ranged from 1:100 to 1:100,00. The engineers were the ones who calculated 1:100 versus NASA management who calculated up to 1:100,000. I remember that when Feynman's numbers were reported, many downplayed the 1:100 possibility of losing another shuttle in a catastrophic failure. It turned out that the 1:100 figure was too optimistic since we lost 2 shuttles out of 135 missions.

While "the unprecedented cold temperatures" may have been the cause of the accident, the Roger's Commission placed much blame on NASA's "decision making process" and lack of a proper safety analysis process. Which to me means that when we dive we need to do a risk analysis of the planned dive to assess the likelihood of a problem occurring and what the outcome (consequences) would be if it occurred and what could be done to modify the risk or outcome; and then accept no unnecessary risk that leads to a significantly bad outcome.

 

[GDI]

Never Rush to your death