Bird incident pyramid true or false?

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Bird incident pyramid true or false?

March 6th, 2011

Health and safety management methods based on the Bird incident pyramid are false, argues Australian safety psychologist David G Broadbent.

Significant Sheq decisions are made based on practitioners fumbling around in veils, mists, half truths and ‘magic mushrooms’, writes David G Broadbent on Transformationalsafety.com in the extract below;

A major health and safety management consulting company is debating these ‘items of faith’. For quite some time I have held similar views. One of my safety presentations some years ago was titled ‘Myths, misdirection and misperception, and misapplication to safety outcomes’.

Health and safety has always been a popular and entertaining song and dance. Has it impacted on organisations taking a scientific view of safety interventions? Who knows.

That is not to say we should not continue to consider some of these myths, and how they might be impacting on the manner in which we go about doing things, including our holy grail, LTIFR, as I have argued before.

We generally believe that the number of LTIs at work is predictive of the likelihood that a major disaster or workplace fatality would occur. This is one of the most emotionally ‘believed’ myths in occupational health and safety.

I was visiting Hong Kong recently; “David, I don’t know what is going on here. We have been working on reducing our near misses and LTIs and they are the lowest they have ever been, yet we continue to kill just as many people every year.”

Sadly, we do know what is going on here! This very senior global CEO has been seduced by one of the myths of safety. Some global safety consultancies base their entire business model on this foundation.

I am reminded of a story I once heard. Two builders constructed some very impressive houses. They had all the “bells and whistles” you could think of. Everything and anything was available. It was like being on one permanent vacation.

Unfortunately, one of the builders had not completed a proper geographical survey. Approximately twelve months after completion there was a minor earthquake, one of those houses fell down around the ears of the owners. As it turned out the house had been built upon a foundation of sand.

We could not easily see that one of them was founded on flawed foundations. No matter what “improvements” the owner might make, they were doomed to failure and the money and emotional investment lost.

The place was always going to fall down when the “system” was put under any significant pressure. Our safety systems are no different. If they are built on foundations of sand, and we are battling against the entropic decay that the poor foundation accelerates.

Safety culture is no myth

The optimal ‘geographical survey’ for a safety system is a recognised safety culture and safety leadership review of the practices going on within the “system”. The source for the above story is Matthew 7, 24 to 27.

Bird Triangle is false

The myths we are concerned about have evolved, over time, via some very questionable quasi science, and I am being generous here. The Bird Triangle, “Safety Triangle” or “Accident Pyramid”, was devised by Frank Bird in the USA. There are now all sorts of derivations as different commentators have tried to put their own “brand” on it.

Based on this triangle, for every 30 000 at risk behaviours, you are likely to experience a major incident or fatality. Nothing could be further from the truth. It is just convenient nonsense, and seems to make intuitive sense, and that is what makes it so dangerous. There is no real science to support the intuition.

The implication is that there is a direct mathematical relationship between the number of near misses occurring on a site and the likely number of major incidents, LTIs, and fatalities. At the very best, one must say this is misleading. At its worst we have to say that it is very dishonestly pedalled about. The higher up the pyramid you go, the less valid is any relationship at all.

Many safety professionals have limited qualifications in safety science itself, and are seduced into thinking there is something factual about the Bird pyramid. Even those people though, you would think, might express some surprise at the base 10 multiples being perfect?

Henrich pyramid does not predict

It was actually Walter Heinrich (Liberty Mutual Insurance) who presented the first incident pyramid in the 1930s. Heinrich is considered the “father” of the BBS approach to safety.

He came up with a pyramid that gave figures to risk exposure. No surprise, he was an insurance guy. Research over the years has shown that the makeup of the Pyramid, and even the shape of it, is unique to each organisation, despite the fact that it is not predictive.

No two companies share the same pyramid. That alone should be ringing alarm bells. Indeed, the major factor which has been shown to impact the shape of an organisational pyramid is the prevailing safety culture functioning inside the business. There’s that ‘foundation’ again.

Bob Eckhardt made the comment as far back as 2003. He also suggested that the accident pyramid, like much of Heinrich’s early work, went unchallenged for so long, that it developed a sense of “fact” and “reality” around it. I agree with Bob.

Any relationship between the variables in the Pyramid is very loose. It is actually a very weak correlational relationship; for those of the readership with any background in fundamental statistics; a weak correlational relationship lacks any real “meaning” at all.

Sports inijury example

Here is an example that I often present in particular safety presentations. What is the most dangerous sport in the world? Parachuting, high speed car racing, skiing, bull riding? The correct answer is Lawn Bowls.

Yes, the pastime that Sir Francis Drake was playing when advised that the Spanish Armada had been spotted off the Elizabethan coast of England.

This is a statistical fact based upon sound correlational mathematics. In fact, the mathematical relationship with regard to the lawn bowls example is much stronger than those which exist within the Pyramid. Why is it then that we so easily see the flaw in the lawn bowls example, and can’t see it in the Pyramid? That’s a much longer journey into the world of cognitive psychology for another day.

Of course, the only reason that lawn bowls is such a “dangerous” sport is the general age demographic of those who invariably play it. So many people do die whilst playing bowls, but it is not the act of playing bowls that significantly contributes to the death. It is a wide range of other factors.

As has already been noted above, with respect to accident causation the existence of a positive resilient safety culture is of far more value than the vagaries associated with the Pyramid.

About the supposed link between “unsafe acts” and “fatality”. Fred Manuele made the point in the Journal of Professional Safety (March 2003) that “Many accidents that result in severe injury are unique and singularly occurring events in which a series of breakdowns occur in a cascading effect.”

Dan Petersen said; “If we study any mass data, we can readily see that the types of accidents resulting in temporary total disabilities are different from the types of accidents resulting in permanent partial disabilities or in permanent total disabilities or fatalities. The causes are different.”

Safety celebrations are false

So in essence some of the world’s formemost safety commentators, both current and past, suggest there is no relationship at all.

Remember Texas City disaster. They had some of their best safety performance, based on Henrich Pyramid or Bird Triangle data, for some years prior to the explosion that killed 15 people.

These sorts of observations showed no relationship to the recent Deepwater Horizon disaster. They were celebrating seven years of excellent safety performance based on Pyramid data at precisely the time the installation caught fire and killed 11 people.

I have heard it said they were actually cutting the cake when the place blew up. I suspect that is somebody trying to make a point. If it was, then it is well made.

By maintaining these myths within our safety systems we continue to be at risk of blowing up the celebration cake. Unfortunately the wider systems within which we operate have way too much invested in the status quo, and seem comfortable enough to just invent bigger and bigger sticking plasters (band aids). At the end of the day do you just want to patch the wound, or do you want to cure the illness.

We are in for a long journey in changing our basic health and safety management assumptions, applications and celebrations.

PHOTO; David G Broadbent, Australian based safety psychologist, who consults clients in India and SA.

==== Comment; alternative metrics?

Ronele Isaacs comments on ‘Bird incident pyramid; true or false safety premise’

Point well made, Bird’s triangle is a measurement dating back decades. Why do industries continue to use LTIF and this triangle, because any indicator is better than no indicator!

Huge corporates have intellectual types employed, why do they condone this use of apparent false information? Its not like it has never been challenged, it always is- among our safety peers as well as from our business and production colleagues.

Many of us can write books on how the LTIF and Bird’s triangle were tracked and used, yet still the companies had multi fatalities and serious disabling injuries. It scary stuff.

Same question always comes up though, WHAT IS THE ALTERNATIVE? If I can get something that is better and more reliable, great! I think that if you are forced to use it, you should not use it as the only source of information or indication of risk and risk behavior.

Risk identification, HAZOPS, HIRAS and the like are all part of a system. You need to scrutinize everything, even IR issues like wage disputes and production shifts, all these could have a bearing on an injury.

Until something tangible and reliable is introduced, industry will continue to use LTIFR and Bird’s triangle to determine bonuses and performance output. Sad, but true.

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Comments

Ronelle Isaacs (2010-9-3)

Ronelle Isaacs comments; Point well made, Bird’s triangle is a metric dating back decades. Industries continue to use LTIF and this triangle, because any indicator is better than no indicator!

Huge corporates have intellectual types employed, why do they condone this use of apparent false information? Its not like it has never been challenged, it always is- among our safety peers as well as from our business and production colleagues.

Many of us can write books on how the LTIF and Bird’s triangle were tracked and used, yet still the companies had multi fatalities and serious disabling injuries. It scary stuff.

Same question always comes up though, WHAT IS THE ALTERNATIVE? If I can get something that is better and more reliable, great! I think that if you are forced to use it, you should not use it as the only source of information or indication of risk and risk behavior.

Risk identification, HAZOPS, HIRAS and the like are all part of a system. You need to scrutinize everything, even IR issues like wage disputes and production shifts, all these could have a bearing on an injury.

Until something tangible and reliable is introduced, industry will continue to use LTIFR and Bird’s triangle to determine bonuses and performance output. Sad, but true.

Andrew Townsend (2011-12-20)

In response to Ronelle’s comments about corporates, I have difficulty to not become impassioned. After 30 years in industry and 10 in safety research, I can with reply with some confidence.

She comments that “huge corporates have intellectual types.” This is incorrect. Huge corporates recruit in their own image. Conformity begets conformity. Intellectuals question established beliefs and values and make corporations feel uncomfortable. They are rarely recruited, and if they are, they are shunted to a non job.

Huge corporates are statiscally naive in handling trended injury data. Metrics are only part of the process, not a complete process in themselves. To rely on metrics as a basis for management is to remain office bound.

There is an alternative. From experience and research, managements that have the least number of adverse events are those that open their eyes and wear out shoe leather, make time to walk and observe the workplace, talk with and listen to workers. This approach is associated with dramatically lower failure rates.

The ability to spot something out of the ordinary and do something about it is of more use that generating numbers.

Risk identification, HAZOP and HIRA are formulaic thought processes that should be confined to analysis of simple process plants. Real world organisations are complex social organisations that cannot be managed by working to a formula. They can however be managed by seeing and hearing what is going on.