Tony McDonald enhanced data integrity in the alphagov/whitehall repository by addressing a critical validation issue in statistics announcements. He implemented logic in Ruby on Rails to ensure that statistics announcements are invalidated when their related publications remain unpublished, thereby reducing the risk of inaccurate government data being released. Employing test-driven development and unit testing, Tony updated the validation mechanisms and aligned the existing test suite to reflect the new rules. This targeted bug fix improved the reliability of the publishing workflow, demonstrating a focused approach to risk mitigation and data accuracy within a complex, production-grade Ruby application environment.