An organization has engaged a third party to implement an application to perform business-critical calculations.

 The most important process to help ensure the application provides accurate calculations is quality assurance (QA), which involves verifying that the application meets the specified requirements and standards, and testing the application for functionality, performance, reliability, security, and usability. QA helps to identify and correct any defects or errors in the application before it is deployed to the production environment. Key performance indicator (KPI) monitoring, change management, and configuration management are important processes for managing and maintaining the application after it is implemented, but they do not directly ensure the accuracy of the calculationsperformed by the application. References: CISA Review Manual(Digital Version), Chapter 3: Information Systems Acquisition, Development & Implementation, Section 3.3: Practices for Quality Assurance