The success of a DLP implementation relies heavily on accurately defining and configuring the policies and rule sets. These configurations ensure that the DLP tool effectively monitors and controls the movement of sensitive data within the organization, thereby preventing data loss.
References
* ISACA CISA Review Manual 27th Edition, Page 301-302 (Data Loss Prevention)

A computer-assisted technique is the most helpful method for an IS auditor to determine whether duplicate vendor payments exist on a complex system with a high volume of transactions. A computer-assisted technique is a tool or procedure that can be used to perform audit tests or procedures on data stored in electronic form. Examples of computer-assisted techniques include data analysis software, query tools, scripting languages, and specialized audit software. A computer-assisted technique can help an IS auditor to identify and extract duplicate payments from a large data set, perform calculations and comparisons, and generate reports and summaries. A computer-assisted technique can also provide more accuracy, efficiency, and coverage than manual methods.
Stratified sampling, statistical sampling, and process walk-through are not as helpful as a computer-assisted technique for this purpose. Stratified sampling is a sampling method that divides the population into subgroups based on certain characteristics and selects samples from each subgroup. Statistical sampling is a sampling method that uses probability theory to determine the sample size and selection criteria. Process walk-through is a review technique that involves following a transaction or process from start to finish and observing the inputs, outputs, controls, and documentation. These methods may be useful for other audit objectives, but they are not as effective as a computer-assisted technique for detecting duplicate payments in a complex and high-volume system. References: ISACA Frameworks: Blueprints for Success, [ISACA Glossary of Terms]

Substantive testing is the most important type of testing during software license audits, as it provides evidence of the accuracy and completeness of the software inventory and licensing records. Substantive testing involves examiningtransactions, balances, and other data to verify their validity, existence, accuracy, and valuation. Compliance testing, on the other hand, is more focused on assessing the adequacy and effectiveness of internal controls over software licensing, such as policies, procedures,and monitoring mechanisms.
Compliance testing alone cannot provide sufficient assurance that the software license audit objectives are met, as itdoes notverify the actual software usage and compliance status. Judgmental sampling and stop-or-go sampling are methods of selecting samples for testing, not types of testing themselves. *References:
According to the ISACA IT Audit and Assurance Standards, Guidelines and Tools and Techniques for IS Audit and Assurance Professionals, section 1206 Testing, "The IS audit and assurance professional should perform sufficient testing to obtain sufficient appropriate evidence to support conclusions reached." 1 The section also defines substantive testing as "testing performed to obtain audit evidence to detect material misstatements in transactions orbalances" and compliance testing as "testing performed to obtain audit evidence on theoperating effectiveness of controls." 1 According to the ISACA IT Audit and Assurance Guideline G15 Software License Management, "The objective of a software license auditis to provide management with an independent assessment relating to compliance with software license agreements." 2 The guideline also states that "substantive tests should be performed on a sample basis to verify that all software installed on devices within scope has been appropriately licensed." 2

The best source of information for an IS auditor to use when determining whether an organization's information security policy is adequate is the risk assessment results. The risk assessment results provide the auditor with an overview of the organization's risk profile, including the identification, analysis, and evaluation of the risks that affect the confidentiality, integrity, and availability of the information assets. The auditor can use the risk assessment results to compare the organization's information security policy with the risk appetite, risk tolerance, and risk treatment strategies of the organization. The auditor can also use the risk assessment results to evaluate if the information security policy is aligned with the organization's objectives, requirements, and regulations.
Some of the web sources that support this answer are:
* Performance Measurement Guide for Information Security
* ISO 27001 Annex A.5 - Information Security Policies
* [CISA Certified Information Systems Auditor - Question0551]