Posted By Bev The company I now work for has a risk rating system with 5 categories. The severity rating makes a certain amount of sense, but the risk rating is as follows: 1. Highly unlikely 2. Unlikely 3. More likely than not 4. Quite likely 5. Almost certain I find 3 and 4 particularly difficult to distinguish between. I've only used rating systems with three or four categories before, but if I change this system to 4, then I will need to alter all of the generic risk assessments, as the ratings will obviously reach a different figure. Has anyone got a rating system which uses 5 or more categories, and if so, could you please let me know what they are and how sensible you think the distinctions are?! I'm looking for something simple that non H&S people will understand. Many thanks.

Posted By NeilM Poyznts-Powell Hi Bev, 1. very unlikely 2. unlikely 3. may happen 4. likely 5. very likely 6. certain. I've sent you a copy of the matrix i'm working on 9based on Croner's). Hope it helps. Regards, Neil

Posted By Merv Newman I think a risk scale which is easier to understand is one based on frequency of exposure : 1 = never or rare (once per year) 2 = 1 to 5 exposures per working week 3 = 1 to 8 exposures per working day 4 = more than once per working hour but not permanent 5 = permanent exposure The question then is "Do my existing control measures reduce the seriousness of the probable injury to level 0 or 1 ?"

Posted By Bev Thanks everyone - you've been really helpful!

Posted By Victoria Kieran Yes this is a difficult one a lot of it is rather subjective, however we graded it with six categories and these were as follows, hope this helps... 0 = Almost impossible, so unlikely that probability is close to zero, 1 = Extremly unlikely - remote probability that event could occur, 2 = Unikely, unlikely though conceivable, 3 = Likely, Probable, occurence could happen, 4 = Very Likely, almost certain to occur/occurence expected 5 = Extremly likely, event only to be expected, no doubt. The main factor is how you train and communicate to personnel on-site (ie risk assessors and the Managers) so they understand, some scenarios pertinent to your business may help the peices to fall into place. Good luck.

Posted By James Fleming · Certain (common occurrence) · Likely (Frequent occurrence) · Probable · Possible · Unlikely (Remote but possible) · Extremely unlikely (Improbable)

Posted By Ian Bennett I have used a system that gives a percentage risk. Probability 1-5 as used before Severity 1-5 as before Add together the probability and severity and multiply by 10 give a percentage risk. Example Probability 3 Severity 2 (3+2=5)x 10 Gives a 50% or medium risk. It looks more logical for the layman

Posted By Aidan Toner I,M having a bad maths day. MICHAEL, I like your system but I,m assuming you meant to say Remote= 1 point and NOT 3 points. I ran a few quick risk situations with your system and I liked it. IAN, when I look at your sum I revert back to 3X2=6 out of a potential 25 which does'nd get me to an overall 50% risk level.?? All comments made by a notoriously bad maths student.!!

Posted By Terry ap Hywel Hi Bev All the replies on this topic illustrate what an area of confusion this is. One of the major problems highlighted by this thread is what do the ratings actually mean for likelihood, severity, frequency - or any other numbers you want to multiply (or add). Unless it is clearly defined within your system what a "very likely" rating actually means it is "very likely" that every person doing the rating exercise will have a different view. Is it really useful to say that "very likely" will occur regularly or almost certain to occur or might occur once a year - does this help in arriving at a rating? I often have students carrying out a rating exercise assessing the likelihood of a hazard causing an accident as "very unlikely" because they have never heard of any accidents caused by that risk. Luckily most people have had very few, if any, experiences of fatal or serious accidents in their workplace so will generally tend to underestimate likelihood if the system is based on this sort of approach. What is the value of risk rating? I find a lot of managers massage the figures to suit whatever system they have. If they have to get below a certain figure they will. The purpose of the exercise is (as Phillip McAleenan said in his reply) to ensure that risks are controlled so I would suggest that, if you are going to carry out risk rating, likelihood should be rated on the basis of the control measures used (or planned) e.g. If no control measures have been provided then it is "Certain" that sooner or later an accident will occur. If the only control measures depend on the worker to use them, such as PPE, then it is "very likely". If the control measures are engineering measures (e.g. a fixed guard), and a maintenance system has been set up, training provided, regular inspection regime, etc. then the rating can be "very unlikely" If you decide on control measures that reduce the risk at source - e.g. low voltage tools - then the severity or consequences side of the equation could be reduced from "death" to "minor injury" If you would like a fuller list contact me directly. Best wishes Terry