Lessons · Accounting · reasonable assurance, not a guarantee
Reasonable assurance, and why not absolute
An audit gives high assurance, not certainty. Testing everything is impossible on any real company, some evidence is persuasive rather than conclusive, and fraud involves people actively hiding things. So the standard is reasonable assurance, which is a deliberate, stated limit rather than an excuse made later.
Hone is a place to practise a career, one idea a day. This is one of its lessons, written out in full and free to read without an account.
In beta. This lesson was written for Hone and has not yet been checked by a qualified accountant. Practice material, not professional advice. What that means.
What it is for
This is the sentence the profession is judged on when something goes wrong, and it is worth being able to say precisely. An auditor who has done everything right can still miss a well-concealed fraud, and an auditor who says nothing about the limit before the event sounds like they are inventing it afterwards.
How to think about it
When asked what an audit guarantees, answer with the limit first and the reason second: high but not absolute, because of sampling, the nature of evidence, and concealment.
Worked example
Not everything can be testedVolume alone makes it impossible on a real company.
Much evidence is persuasive rather than conclusiveAn invoice supports a sale. It does not prove the goods moved.
Fraud involves concealment, often by more than one personCollusion defeats controls designed for individuals.
So: high assurance, not certainty, and stated in advanceThe limit is part of the product, not a defence.
Your turn
Name the level of assurance an audit provides.
An audit provides assurance rather than absolute certainty
Solve one, graded on the server
The trap
Treating reasonable assurance as a low bar. It is a high one. It means the auditor has reduced risk to an acceptably low level by doing enough work, not that they did what they could and hoped.