Like many organisation, mine likes to express risk rating quantitively. I keep coming up against the same two siders to the following and as I can find nothing definitive am looking for a consensus. When considering the severity of a hazard, which holds more true? 1. Always take the worst case scenario ie. death from banging your head during a fall or exposure to fire or electricity . 2. Accept that fatality may not be the outcome (Probable outcome) and so reduce the severity rating. I'm sure I'm not the only one to have come across this discussion and will be interested to see the different perspectives on the subject.

Graham I use the following sliding scale: Major / Fatality / Disability Serious / Major Injury Concern/ 3 Day Injury Noticeable/ Minor Injury Slight / No Injury Again there is a quanative score to go with it but would like to take one of the ratings out to end up with a four by four rating grid (already have four catagories for the likelihood) to force a decision away from middle ground as often seen on the 3x3 or 5x5 grids. The trouble then would be the erring on the side of caution ending with a more consistant lower score which gives a non suitable and insufficient RA. As Bob said "severity outcome may be death then mark it down as such; as I can assure you that a court will do so". Also the HSE from that which I've read always pick on the RA as insufficient where they cannot get directly at a person. So they build a casse form various points. Badger

You go for the most likely or most probable outcome, otherwise the potential severity will always be death as you can die from just about anything (even a paper cut to the finger). This is where I get cross with an OTT approach taken by some thinking it will protect them if something goes wrong, when it won't. The HSE will want to see that you've taken a reasonable, sensible and pragmatic approach. By opting for the most extreme outcome it shows a lack of understanding of the process. In fact I was discussing the very same thing with an ex-colleague of mine recently (who is still an inspector). In fact the HSE don't actually support the use of numbered rating systems, which they believe to be arbitrary. They want to see that you've thought about the hazard, the risk and the control. And Barrie what nonsense. The HSE don't pick on the RA when they can't directly get a person. That's not how the investigative process works.

In general you should (IMHO) consider a combination of the most likely outcome and the most severe realistic outcome. So in jwk's example I'd stop at a cut finger. For fall from height (obviously dependant on the height, type of ground etc) I'd certainly be looking at broken bones, and for higher falls onto solid (e.g. concrete surfaces) then dealth is a realistic outcome

:-( Do you really think I'm so wrong so much of the time with the competency of my advice? I know I'm a mouthy mare inclined to give my opinion in a matter of fact fashion but I'd like to think I'm fairly competent in the advice I offer.

Claire: That comment was meant to do 2 things: emphasise the fact that I agreed with you and also to have a little (gentle) fun-after all, life's too short etc.

I tend to give more credence to the advice and opinions of Clairel seeing as she has seen and experienced H&S from both sides of the fence. Not that I necessarily agree with all of her opinions but her advice is usually sound (IMHO). Joe

But I could actually be a fat old man who's never even seen the inside of a factory let alone been an inspector. I may just pretentd to be a young lady, ex-inspector, with a bit of experience under my belt so that I can come on here and be an opinionated pain in the butt!!!

Sorry - I can't agree with Clairel in this case. To suggest you go for the "most likely or most probable outcome" appears, in my opinion, to completely miss the point. Maybe it is the choice of words. I think David Jones has it right when he talks about a "realistic outcome." Also, to pick up on what Gordonhawkins said - "the only thing useful about such a system is that it can be used for prioritisation." Again in my opinion, that is the whole point. Many companies struggle with H&S because they don't prioritise properly. Kate - thanks for your comment.

Sredman I personally believe that Tony is arguing that only competent persons should be using matrices as they have the necessary skills to understand what is being done. That said however there is such a thing as intersubjectivity and an organisation can use this to even out the variations in matrix use with adequate training etc. Problem is that most processes using a matrix are poorly drafted and obscuring the actual process needed to achieve a sensible solution. Given proper training most supervisors can achieve a sensible answer concerning risk and its control measures. I used the ladder analogy above but this is in itself a poor representation of what makes a good risk assessment as the most useful assessments are for a complete task not a single part such as gaining access to the work area via a ladder. Matrices allow us an indication of whether adequate control has been achieved for a specific risk and thus whether further specific controls are required if control is unsatisfactory. Any assessment that provides a "high" severity/risk has to be further controlled and this is where a matrix scores heavily as it provides relatively good accuracy for the speed of determination. I say again though adequate training is the key - ie at least 4 hours plus assessment and follow up post training to ensure repeatability and proper use of the process. Bob

Formal risk quantification will only ever be possible in a determinate engineering environment and matices are then superfluous. We should be using any final quantity as a guide not an absolute quantification Bob

The trouble with the "most likely or most probable outcome" is that usually this outcome is - nothing. "I've done this a hundred times and never been hurt". I'm sure this isn't what clairel really means!

But suppose that for some fall from an intermediate height where death is possible but not certain the outcome probabilities (ignoring the no-injury possibility) are (for example) minor injury 50%, fracture 40%, death 10%. The most probable outcome is a minor injury but that's not the one that you'd base the assessment on, is it?

Ray, it is about a judgement call and that's why no two professionals will ever agree on the content of a RA!! Kate, I would disagree with your severity outcome. A fall from an intermediate height (say a stepladder) for me would most likely result in a major injury not a minor injury. Yes death is a possibility and does happen but it is still most likely to be a major injury (in my expereince of invstigating accidents). Therefore the controls would reflect this as the most probable outcome (do you understand whay I am using that term now??). I think that what people forget is that the reason for the severity assessment (whether it be in the form of a rating number or a rating group (eg, low, medium, high) or just a description) is to determine the level of controls required. The reasonably practicable application requires assessment of outcome. ie you would be expected to dedicate more time and money (control measures) for a potential death or even a potential major injury than you would for a minor injury. That is the puporse of a severity assessment. That was the point of my first post. If everything was deemed to be potentially fatal then we would be expected to dedicate a disproportinate amount of resource to the control measures for that. Kate, I think we actually agree you're just not getting what I'm saying.

For my twopenneth... If you ask everyone who has contributed to this thread to assess the likelihood of injury occurring for a set task you would have 10-12 different valuations. Don't assess the numerical value of falling off a ladder or the %age likelihood of an injury occurring - avoid work at height where possible. If you must do work at height then assess if using a ladder is the safest and most appropriate way of doing the job - if it is, assess what is the right type of ladder for the job, which personnel are competent to undertake the task, other factors (like tying off or passing traffic) that decrease/increase risk and reduce the hazards as far as reasonably practicable. In short - put together a combination of activity, equipment, personnel and environmental factors to ensure a safe job can be undertaken. Follow legal standards (primarily WAH and PUWER) and be familiar with relevant guidance such INDGs 401, 402, 405.

Taking Kate's example above, I would consider death as the highest severity 'realistic' outcome - hence why I consider realistic as opposed to possible - as others have stated death is a possible outcome (direct or indirect) of many incidents but may not be realisitic given the particular circumstances required for it to occur, so in thiose case I'd generally consider a lower severity outcome for comparative/prioritisation purposes. NOTE that does not mean that the risks should be ignored, but living in the real world decisions have to be made on which risks to control first and dedicated the limited resources to (I use limited as again in the real world there is always a finite amount of time, effort, money etc available)

I'd have to agree Ray that people are getting too hung up on the minor details of percentages and ratings instead of just looking at the control measures needed to prevent injury.