Glossary›Assurance, audit evidence and working papers›Sufficient appropriate evidence
Glossary term
Cluster A · A3
Tier 1 · differentiator
Sufficient appropriate evidence
Definition
Sufficient appropriate evidence is the two-part test an assurance provider applies to everything it collects. Sufficiency is quantity: enough items tested to support the conclusion. Appropriateness is quality: the evidence must be relevant to the specific assertion and reliable in origin. External, independent, contemporaneous records rank above internal records prepared after the fact.
On this page
In practice
The two halves trade against each other in one direction only. Better evidence means you need less of it. More evidence does not fix evidence of the wrong kind. Fifty internal spreadsheets do not add up to one invoice.
The level of assurance changes how much is needed. In limited assurance the assurer needs enough evidence to say nothing came to their attention. In reasonable assurance they need enough to state a positive opinion, which is materially more work on the same numbers.
What the assurer does with it
The assurer sets a materiality threshold, identifies where misstatement is most likely, and allocates testing accordingly. They test a small number of very large items completely and sample the tail. If testing produces errors, sufficiency is no longer satisfied and the sample expands. The trigger for a difficult conversation is a sample error rate that, projected across the population, would exceed materiality. At that point the assurer stops sampling and asks the entity to investigate the whole population, which is expensive and late.
Commonly confused with
“Enough documentation.” Volume is not sufficiency. A file can be enormous and still fail, because the documents in it do not speak to the assertion under test.
Sources
1
ASSA 5000 General Requirements for Sustainability Assurance Engagements
AUASB
2
Review status
Review required
Last reviewed
15 September 2026
Editorial pass, unsigned
Reviewer required
Registered company auditor
Next scheduled review
1 July 2027
Part of
Cluster A, Assurance, audit evidence and working papers
47 terms on what an assurance provider tests, what they accept as evidence, and what a preparer has to be able to produce.
Related terms
What counts as evidence before the two-part test is applied
How sufficiency is turned into a number of items tested
What happens when sufficient appropriate evidence cannot be obtained
Related questions
What evidence do we need for each emissions number?
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Every reported number needs a source document you did not create for the report, the activity data drawn from it, the emission factor and its published edition, and the calculation joining them. Fleet fuel needs litres from fuel card statements, electricity needs kWh by site from retailer invoices with the matching state factor, and refrigerants need kilograms by gas type from service records.
What does an assurance provider actually test in year one?
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In year one they test the disclosures inside the ASSA 5010 first-year scope: Scope 1 and Scope 2 emissions, governance disclosures, and specified strategy paragraphs on climate risks and opportunities. The work runs in a predictable order, from understanding your reporting process and your boundary, through sampling source documents and reperforming calculations, to written representations at the end.
Other terms in this cluster
Sufficient appropriate evidence