Vouching is a manual audit procedure where the auditor tests the validity of transactions or records by tracing them backward from the final records to the original source documents. This technique helps verify the authenticity and accuracy of the entries in the accounting records by ensuring that each entry is supported by proper documentation. For example, an auditor might start from an entry in the general ledger and trace it back to the original invoice or receipt to ensure its validity.
IIA Global Technology Audit Guide (GTAG) on Understanding and Auditing Big Data IIA Standard 2310: Identifying Information

Conflict of Interest: For both assurance and consulting engagements, it is crucial to avoid conflicts of interest.
An auditor assessing processes they were previously responsible for can compromise objectivity and independence.
IIA Standards: The IIA ' s Code of Ethics and standards emphasize maintaining objectivity and avoiding conflicts of interest. This is particularly important in consulting engagements where the auditor ' s recommendations could be influenced by prior roles.
Appropriate Action:
Assurance Engagements: For assurance engagements, prior knowledge might be beneficial but still raises concerns about independence. Declining the consulting engagement due to previous responsibilities ensures objectivity.
IIA Standard 1130 - Impairment to Independence or Objectivity.

For audit evidence to be considered reliable, it must be accurate, truthful, and verifiable. The absence of the bank heading, logo, or address on the bank statements raises concerns about the authenticity and integrity of the documents. Without these elements, there is no assurance that the statements are legitimate and have not been tampered with or falsified. Therefore, this evidence may not be reliable for audit purposes.
The Institute of Internal Auditors (IIA), International Standards for the Professional Practice of Internal Auditing (Standards)
"Auditing: A Risk-Based Approach to Conducting a Quality Audit" by Karla M. Johnstone, Audrey A.
Gramling, Larry E. Rittenberg

According to the IIA Standards, the primary factors in determining the adequacy of an annual audit plan include sufficiency, appropriateness, and effective deployment of resources. These elements ensure that the internal audit activity can effectively cover key risk areas, provide relevant assurance, and utilize resources efficiently. While cost-effectiveness is important, it is considered less critical compared to ensuring the audit plan is comprehensive and appropriately targeted. References: = IIA Standard 2010 - Planning.

Internal auditors generally determine the priority of the areas within the engagement scope by assessing the risk of those areas. This involves estimating the likelihood of a risk occurring and the potential impact of that risk on the organization. High-risk areas with a high likelihood of occurrence and significant impact are prioritized to ensure that critical risks are addressed promptly. This risk-based approach to prioritization helps ensure that the audit resources are focused on the most significant areas, enhancing the effectiveness and efficiency of the audit.
The Institute of Internal Auditors (IIA) - Standards for the Professional Practice of Internal Auditing, Standard
2010 - Planning