ALARP
ALARP means a risk has been reduced as low as reasonably practicable: further reduction would require sacrifice grossly disproportionate to the benefit gained. Demonstrating ALARP means showing your controls, not just your risk matrix.
ALARP is the risk-acceptance test at the heart of UK-derived safety regimes: a duty-holder must reduce risk until the cost of further reduction — in money, time, or trouble — would be grossly disproportionate to the additional safety gained. It is not "as low as we could afford" and not "as low as the matrix says is green"; it is a demonstration, made with evidence, that the remaining risk has been earned.
The demonstration is where bowties do their work. An ALARP argument is, in substance, a claim about barriers: these are the controls in place, this is their effectiveness, these further options were considered and rejected on proportionality grounds. A bowtie diagram puts that entire argument on one reviewable page, which is why regulators and safety-case assessors so often ask for one.
Australian WHS law expresses the same idea through different words — SFAIRP, "so far as is reasonably practicable". The tests converge in practice; the vocabulary differs by jurisdiction, and Australian duty-holders should write to SFAIRP.
The practical trap: ALARP established once, then quietly eroded. The argument depends on the barriers staying effective, which is why degradation factors and ongoing verification are part of the demonstration, not an optional extra.
Last reviewed 2026-08-09 · Back to the glossary
See the method in working software.
Six worked bowtie examples ship with the product — open one read-only, no sign-in, and read every control in full.