We have experience ranging back from the ACC WSMP audits to our own case law based reality versions. Yes, the original audits were nothing more than a revenue gathering box ticking exercise that actually provided a false sense of security, particularly when blanket applied across distributed organisations. The acid test is; have the audits reduced our statistics? No.
For all their failings, WorkSafe Inspectors sometimes provide a better (?) snapshot of performance. We follow a litany of improvement notices where the general outcome is a safer work environment for the client. If WorkSafe could get over their "not here to consult" approach they could provide a not-bad service lol!
Ben Hutchinson's work can easily be ratified by comparing Case Law (disaster) with the organisations H&S audits. What was the root cause of the disaster? How effective was the audit at detecting the weak signals? Our experience (including a fatality) validates Hutchinsons assertions.

Audits tend to be a snap shot of a sample tested against some kind of standard. Usually to determine a level of compliance. They never determine that you are a "safe" organisation.

There purpose isn't to pick up "weak signals". Though you may have a good auditor who will notice non-audited things and will make either verbal / suggestions / recommendations or will make them in the audit report.

It would be foolish to rely on audits as a method for picking up potential disaster warnings. We need to be much more proactive than that.

I think you're missing what an audit is. It sits squarely in the assurance realm, not in the identification part of your safety management system.
Particularly if you're looking for "weak signals" it will not be effective; that is better left to those who know the processes best.

I think it very much depends on what you do with the audit and the findings after the fact. an audit is a snapshot in time, and will give you findings based on both the evidence supplied and the experiance of the auditor.
if you take the audit, have a good look at he recommnedations, implment the ones that are effective, and then in the following audit review the last one (or more) in the review of the next audit, they can be effective. Alas this does not happen very oftern.
Also what is very important is the scope of the audit to ensure that any expoected outcomes are achived.

My thinking:
When an audit happens, the site will put their best foot forward which might, and I say might, not be the actual state of work at any given time. Yes, this is needed and I have seen, having recently moved to Australia(Brisbane) in CC Infrastructure, those on the frontline are really eager to understand what is being audited and take on board what is talked about at the audits(we have an internal compliance/ audit team) and I tag along to my sites to support my frontline staff(Civil Construction) - Improvement Opportunities are needed and we have seen the sites and staff come a long way since January with having the correct documents needed onsite for High Risk work(SWMS, Pre-starts and Risk Assessments, etc) - but the understanding that they need to make it site specific and not generic was a challenge, understanding that they are "allowed" to touch and and change paper work(generic stuff) on site to be more site specific and my team being present at the audits, has built more confidence. We had member of the public report us to WHSQ that our mobile plant was too close to the road, we did not know an inspector went out and watched the work being done for an hour, the inspector then presented himself(did not have his white card on him.....) and then looked at the documentation - and the site passed with flying colours, this I dont think would have been the case 12months earlier. Sorry If I have been rambling on and totally missed the point :)
Oh and we were compliant with the proximity of the mobile plant to the road too :)

Aaron, I'm inclined to agree with you in respect Management and Board "assurance" with conducting audits. However, in my view the result will only be as good as the auditor and their use of open questions.
The starting point for every audit is agreeing the SCOPE with the owner.

yeah,but no audit, however good will replace proactive reporting.

External audits are always useful for helping a safe system of work remain structured and on track.  Audits not detecting 'weak signals' that warn of disaster may be a reflection of the auditor. A competent and experienced auditor should be able to look past the paperwork. The questions auditors should be asking is not show me the paperwork rather show me an example, show me the evidence. Win-win. Audits are not there to catch you out they are there to help you out.