From the Preface: "Data from outside sources are often central to audits. While these data are simply one type of evidence that auditors rely on, appropriately assessing their reliability may require more technical effort than other types of evidence. The purpose of this guide is to describe the principles behind and steps involved in assessing the reliability of data used for audits. This guide is consistent with the Yellow Book -- the 2018 'Government Auditing Standards' -- which defines generally accepted government auditing standards (GAGAS), and supersedes GAO's [Government Accountability Office] 2009 guidance, 'Assessing the Reliability of Computer-Processed Data.' This guidance covers computer-processed data, referred to in this document simply as 'data', which result from computer processing or entering data into a computer system. [...] This guide provides a flexible, risk-based framework for data reliability assessments that can be geared to the specific circumstances of each engagement."
Government Accountability Office: https://www.gao.gov/