One of the stranger beliefs that emerged in the risk 'business' in the last decades of the 20th century was the idea that risk assessments could be wholly scientifically objective. That is, a belief that risk is purely a physical property of the natural material time-space universe that can be independently and objectively measured.

Australian parliaments collectively seemed to have adopted this 'scientific' risk view as demonstrated by the insistence under OHS legislation that all 'hazards' should be risk assessed on all occasions. Not complying is usually an offence in itself, irrespective of the precautions adopted to address the 'risk'. The concept seems to be that similar risks in different places would be similarly assessed and judged by different people enabling similar appropriate precaustions to be implemented. Human cultural and cognitive differences ought not to be significant.

Amongst other thing, if all this were true, two independent experts assessing the identical threat scenario would arrive at similar risk characterisations. In practice, this simply does not happen, to the frustration of regulators, senior decision makers and the community generally. And, it is not a position with which the courts have ever necessarily agreed.

The review by Maxwell QC of the Victorian OHS Act in 2004 culminating in the adoption of the new OH&S guidelines in July 2007 appears to confirm this. (Chris Maxwell is now a Victorian Supreme Court Judge and President of the Court of Appeal). The Regulatory Impact Statement, Occupational Health and Safety Regulations 2007, Equipment (Public Safety) Regulations 2007 indicates that:

'Further, mandating risk assessments maybe a barrier to the implementation of risk controls. For example, where hazards and risks are well known and there are universally accepted control measures, a duty holder may identify the hazard and implement the appropriate control without doing a risk assessment. In these cases, a risk assessment would yield no new knowledge and would be likely to delay the implementation of controls.'

He is less interested in risk and more interested in precautions. This has been the common view of judges. For example, High Court Chief Justice Sir Harry Gibbs in 1982 noted:

'Where it is possible to guard against a foreseeable risk, which, though perhaps not great, nevertheless cannot be called remote or fanciful, by adopting a means, which involves little difficulty or expense, the failure to adopt such means will in general be negligent.' Turner v. The State of South Australia (1982) (High Court of Australia before Gibbs CJ, Murphy, Brennan, Deane and Dawson JJ).

Big nasty events are always determined to be rare by risk experts, before they occur. If such low likelihoods were practically achieved such events would be so rare that they would no be expected to happen in our lifetimes. This means that if one does occur, the estimation of rarity must have been flawed. As one judge in Australia has commented during an inquiry after a particularly awful event: "What do you mean you didn't think it was going to happen, there are 7 dead".

This is a powerful argument and one which cannot be supported by the traditional risk based hazard management that suggest target levels of risk are acceptable or tolerable in some way. Credible, critical threats must be seen to be managed. The judicial test is not based on the level of risk per se, but rather on whether all reasonable practicable precautions were in place in view of the criticality of the outcomes. This is shown in the diagram below.

However, using such risk assessments to rank the available precautions generally does create identical action lists of things to do enabling the decisions makers to determine the level of precautions based on the level of available resources. This seems to be a legally defensible, albeit more complex, process.

Negligence does not seem to arise because some (objective) risk target wasn't met. It arises because the precautions in place were not commensurate with the risk. Unless called up by statute, risk targets in this context are a step on one of the possible due diligence journeys and not ends in themselves. This due diligence argument that demonstrates that all reasonable practicable precautions are in place appears to underlie the revision of the Victorian OHS Act and reulations which come into force in July 2007, and the opinion of the High Court.