Worked on the world-federation-of-advertisers/cross-media-measurement repository, delivering a comprehensive refactor of metric definitions to support both time-based and frequency-based analytics. The approach involved introducing explicit start and end times, as well as a new MetricFrequencySpec, to enhance the flexibility and accuracy of metric scheduling. By removing the previous WindowingSpec and updating the ResultGroup structure, the changes enabled clearer reporting and laid the foundation for more robust analytics pipelines. The work was implemented using Protocol Buffers and the proto language, focusing on schema evolution and data modeling to improve the clarity and maintainability of metric computation logic.