69. The external auditor obtains sufficient appropriate audit evidence about whether accounting estimates and the related disclosures are reasonable [ISA 540 (Revised), Auditing Accounting Estimates and Related Disclosures, paragraph 11.]. Audit evidence is information used by the external auditor in arriving at the conclusion on which the external auditor's opinion is based [ISA 500, Audit Evidence, paragraph 5(c).]. Where the risk of material misstatement is higher, the external auditor requires audit evidence that is more persuasive [ISA 330, The Auditor's Response to Assessed Risks, paragraph 7b; ISA 540 (Revised), Auditing Accounting Estimates and Related Disclosures, paragraph 18.]. As it is expected that the external auditor will assess significant risk(s) of material misstatement related to the ECL estimate [See Expectation 4 within section 2.2, Supervisory expectations for the external auditor on "Assessment of risks of material misstatement".], the external auditor will need to obtain highly persuasive evidence in addressing the risk. If the external auditor does not obtain sufficiently persuasive evidence, there is a risk that fraud or errors (including those arising from management bias) have gone undetected and the ECL estimate and related disclosures may be materially misstated.