Risk-based auditing is an audit approach that focuses on the analysis and management of risk within an organization. Risk-based auditing helps identify and prioritize the areas or processes that pose the highest risk to the organization's objectives and allocate audit resources accordingly. Risk-based auditing also helps provide assurance and advisory services related to the organization's risk management processes and controls.
By using risk-based auditing, internal auditors can optimize the use of their audit resources and add value to the organization.
Agile auditing, continuous auditing, and outsourced auditing are not audit approaches that are most helpful in optimizing the use of IS audit resources. Agile auditing is a flexible and iterative audit methodology that adapts to changing circumstances and stakeholder needs. Continuous auditing is a method of performing audit activities on a real-time or near-real-time basis using automated tools and techniques. Outsourced auditing is a practice of contracting external auditors to perform some or all of the internal audit functions. These audit methods may have some advantages or disadvantages depending on the context and objectives of the audit, but they do not necessarily optimize the use of IS audit resources.

The most important input during the planning phase for an audit on the implementation of a bring your own device (BYOD) program is policies including BYOD acceptable user statements. Policies are documents that define the organization's objectives, requirements, expectations, and responsibilities regarding a specific topic or area. BYOD policies should include acceptable user statements that specify what types of personal devices are allowed to connect to the corporate network, what security measures must be implemented on those devices, what data can be accessed or stored on those devices, what actions must be taken in case of device loss or theft, and what consequences will apply for non-compliance. Policies including BYOD acceptable user statements can provide an IS auditor with a clear understanding of the scope, criteria, and objectives of the BYOD program audit. Findings from prior audits, results of a risk assessment, and an inventory of personal devices to be connected to the corporate network are also useful inputs for planning a BYOD program audit, but they are not as important as policies including BYOD acceptable user statements. References: ISACA CISA Review Manual 27th Edition, page 381.