What factor is critical when determining the authorization of program changes in application maintenance?

When determining the authorization of program changes in application maintenance, the approval log for all program changes is critical because it serves as a documented reference that outlines which changes have been formally authorized and by whom. This log ensures that changes are not only tracked but are also made following an established approval process, contributing to accountability and governance in the application maintenance process.

Having a proper approval log helps to maintain control over the application environment, reduces the risk of unauthorized changes, and supports compliance with organizational policies and regulatory requirements. It can also facilitate auditing and review processes, enabling organizations to verify that all modifications have received the necessary approvals before implementation, ensuring that changes align with business objectives and security standards.

In contrast, while the history of system changes, the timestamp of maintenance actions, and the identity of users applying changes may provide valuable information, they do not inherently indicate whether those changes were properly authorized, which is essential for effective change management.