ISA 540 - Estimates ISA 540 - Estimates Even though the standard has been revised, the latest revision will only be effective for periods commencing from 15 December 2019. This means that the current version is still valid and warrants consideration when auditing estimates. The auditing of estimates has been the downfall of many an auditor during regulatory inspections, as the requirements are often overlooked when auditing fair value valuations, impairment considerations, bad debt provisions and depreciation considerations. Very often, these are the areas [...]