During a post-implementation review for a new system, users voiced concerns about missing functionality. Which of the following is the BEST way for the organization to avoid this situation in the…

Testing system reliability and performance focuses on technical aspects like uptime and speed, not on whether the system possesses the correct business functionality for users.

Adopting an Agile development approach promotes iterative development and user feedback, which can *help* reduce missing functionality, but UAT is the specific, formal stage designed for *final validation* by end-users.

User Acceptance Testing (UAT) is a critical phase where end-users directly test the system to ensure it meets their business requirements and expected functionality in a real-world scenario. By involving users to validate features and workflows *before* final deployment, UAT directly identifies and addresses any missing functionality or usability issues from the user's perspective, preventing such concerns post-implementation.

Adopting a phased changeover approach relates to the deployment strategy, gradually introducing the new system, but it does not inherently prevent the problem of missing functionality prior to deployment.