google/meridian
Dec 2024 – Feb 2026
13 Months active
Languages Used
PythonSQLHTMLJavaScriptMarkdownJAXTensorFlowYAML
Technical Skills
Backend DevelopmentData AnalysisData EngineeringData ModelingData ValidationMachine Learning
Andy Tan
PROFILE
Andy Tan
Andy Tan developed core backend and analytics features for the google/meridian repository, focusing on scalable data ingestion, model evaluation, and multi-backend machine learning workflows. He engineered a unified abstraction layer supporting both TensorFlow and JAX, enabling flexible numerical operations and reproducible sampling. Andy enhanced data validation, visualization, and serialization, improving analytics reliability and test coverage. His work included optimizing adstock calculations, implementing device-aware performance paths, and consolidating CI/CD pipelines for deterministic testing. Using Python, JAX, and SQL, Andy delivered maintainable, extensible solutions that improved model accuracy, backend interoperability, and release stability, demonstrating depth in backend development and statistical modeling.
Overall Statistics
Feature vs Bugs
79%Features
Repository Contributions
112Total
Bugs
6
Commits
112
Features
23
Lines of code
49,592
Activity Months13
Your Network
4412 peopleSame Organization
@google.com4397
Benedict OdaiMember
Craig IngramMember
KayyuriMember
Scott SuarezMember
Agent2Agent (A2A) BotMember
Andreas AbelMember
Aadi KapurMember
Aadish GoelMember
Aahil MehtaMember
Shared Repositories
15
Avishai HalevMember
Amer ElsheikhMember
Edgar ZhuMember
Jeff LiMember
Ken LuoMember
Lolita NazarovMember
Lukasz MazurekMember
The tunix AuthorsMember
Azis AlvriyantoMember
Work History
February 2026
5 Commits • 3 Features
Feb 1, 2026February 2026 (Month: 2026-02) – Developer monthly summary for google/meridian. Focused on enabling robust backend interoperability, CPU/GPU performance, and scalable Bayesian inference workflows.
5 Commits • 3 Features
Feb 1, 2026February 2026 (Month: 2026-02) – Developer monthly summary for google/meridian. Focused on enabling robust backend interoperability, CPU/GPU performance, and scalable Bayesian inference workflows.
February 2026
January 2026
2 Commits • 2 Features
Jan 1, 2026Month 2026-01 — google/meridian: Backend enhancements and stability improvements delivered. Implemented adstock_process for the JAX backend to optimize adstock calculations via convolution, improving performance and accuracy in media spend analysis. Upgraded NumPy dependency to ensure stability and compatibility with future releases (pin to < 2.4.0). No major bugs fixed this period. Business impact includes faster, more reliable media spend analysis and reduced risk from dependency drift; foundation laid for further analytics optimizations.
January 2026
2 Commits • 2 Features
Jan 1, 2026Month 2026-01 — google/meridian: Backend enhancements and stability improvements delivered. Implemented adstock_process for the JAX backend to optimize adstock calculations via convolution, improving performance and accuracy in media spend analysis. Upgraded NumPy dependency to ensure stability and compatibility with future releases (pin to < 2.4.0). No major bugs fixed this period. Business impact includes faster, more reliable media spend analysis and reduced risk from dependency drift; foundation laid for further analytics optimizations.
December 2025
26 Commits • 3 Features
Dec 1, 2025December 2025 was centered on stabilizing Meridian CI, enhancing test reliability, and delivering improvements that increase pipeline efficiency and release confidence. Key actions included hardening CI determinism by disabling parallel Python unit tests, addressing flaky tests through data-shifting adjustments, and enabling cancellation of in-progress CI workflows to reduce wasted compute. On the testing front, we consolidated and refactored the analyzer test suite into a comprehensive framework (AnalyzerComprehensiveTest/AnalyzerTest), improving coverage, consistency, and maintainability across KPI, ROI, CPIK, and related test groups. Collectively, these changes reduce flaky outcomes, shorten feedback loops, and strengthen analytics fidelity for better business decisions. Technologies and practices leveraged include Python, CI/CD workflow configuration, test design and parameterization, vectorized data operations, and robust mocking.
26 Commits • 3 Features
Dec 1, 2025December 2025 was centered on stabilizing Meridian CI, enhancing test reliability, and delivering improvements that increase pipeline efficiency and release confidence. Key actions included hardening CI determinism by disabling parallel Python unit tests, addressing flaky tests through data-shifting adjustments, and enabling cancellation of in-progress CI workflows to reduce wasted compute. On the testing front, we consolidated and refactored the analyzer test suite into a comprehensive framework (AnalyzerComprehensiveTest/AnalyzerTest), improving coverage, consistency, and maintainability across KPI, ROI, CPIK, and related test groups. Collectively, these changes reduce flaky outcomes, shorten feedback loops, and strengthen analytics fidelity for better business decisions. Technologies and practices leveraged include Python, CI/CD workflow configuration, test design and parameterization, vectorized data operations, and robust mocking.
December 2025
November 2025
15 Commits • 1 Features
Nov 1, 2025November 2025 achievements for google/meridian: Delivered JAX backend integration across core components (model, analyzer, optimizer) with serialization, hyperparameters handling, and testing framework; added JAX input compatibility for pandas/xarray; improved RNG reproducibility and introduced deterministic testing. Established CI/test infrastructure to support dual backends (TensorFlow and JAX).
November 2025
15 Commits • 1 Features
Nov 1, 2025November 2025 achievements for google/meridian: Delivered JAX backend integration across core components (model, analyzer, optimizer) with serialization, hyperparameters handling, and testing framework; added JAX input compatibility for pandas/xarray; improved RNG reproducibility and introduced deterministic testing. Established CI/test infrastructure to support dual backends (TensorFlow and JAX).
October 2025
2 Commits • 2 Features
Oct 1, 2025Performance summary for 2025-10: Delivered JAX backend integration for prior_sampler in google/meridian, enabling stateful RNG via PRNGKeys and ensuring proper handling of JAX's stateless RNG within sampling methods; updated tests to reflect the switch from error to warning for set_random_seed in JAX. Also performed code formatting and readability cleanup in model.py and model_test.py to improve maintainability, with autoformatting committed. Overall, these changes improve reproducibility, reliability of sampling under JAX, and code quality for future enhancements.
2 Commits • 2 Features
Oct 1, 2025Performance summary for 2025-10: Delivered JAX backend integration for prior_sampler in google/meridian, enabling stateful RNG via PRNGKeys and ensuring proper handling of JAX's stateless RNG within sampling methods; updated tests to reflect the switch from error to warning for set_random_seed in JAX. Also performed code formatting and readability cleanup in model.py and model_test.py to improve maintainability, with autoformatting committed. Overall, these changes improve reproducibility, reliability of sampling under JAX, and code quality for future enhancements.
October 2025
September 2025
18 Commits • 2 Features
Sep 1, 20252025-09 monthly performance: Delivered cross-backend Meridian consolidation with JAX support, enabling unified backend usage across visualization, testing, and sampling. Introduced backend-agnostic utilities and RNG handling to ensure consistent, cross-backend operation and reproducibility. Implemented runtime backend selection via MERIDIAN_BACKEND and serialization compatibility across components, simplifying cross-backend experiments and deployments. Enhanced Adstock and Hill calculations for cross-backend compatibility, including JAX boolean masking and fixed channel alignment. Expanded testing to validate both TensorFlow and JAX backends and adjusted tolerances to accommodate backend-specific behavior. Improved code quality and data serialization (e.g., prior_distributions and related utilities) to support stable, repeatable results across environments.
September 2025
18 Commits • 2 Features
Sep 1, 20252025-09 monthly performance: Delivered cross-backend Meridian consolidation with JAX support, enabling unified backend usage across visualization, testing, and sampling. Introduced backend-agnostic utilities and RNG handling to ensure consistent, cross-backend operation and reproducibility. Implemented runtime backend selection via MERIDIAN_BACKEND and serialization compatibility across components, simplifying cross-backend experiments and deployments. Enhanced Adstock and Hill calculations for cross-backend compatibility, including JAX boolean masking and fixed channel alignment. Expanded testing to validate both TensorFlow and JAX backends and adjusted tolerances to accommodate backend-specific behavior. Improved code quality and data serialization (e.g., prior_distributions and related utilities) to support stable, repeatable results across environments.
August 2025
18 Commits • 2 Features
Aug 1, 2025August 2025 monthly summary: Implemented foundational backend abstraction enabling multi-backend support (JAX, TensorFlow) across Meridian core modules and centralized backend ops under meridian.backend, enhancing testability, maintainability, and future extensibility. Expanded analytics capabilities with Organic RF support across Analyzer, Hill curves, and plotting, with docs and tests updated. Other notable improvements include deterministic RNG seeding in prior_sampler and migration of components to the backend API (backend.Tensor usage, etc.).
18 Commits • 2 Features
Aug 1, 2025August 2025 monthly summary: Implemented foundational backend abstraction enabling multi-backend support (JAX, TensorFlow) across Meridian core modules and centralized backend ops under meridian.backend, enhancing testability, maintainability, and future extensibility. Expanded analytics capabilities with Organic RF support across Analyzer, Hill curves, and plotting, with docs and tests updated. Other notable improvements include deterministic RNG seeding in prior_sampler and migration of components to the backend API (backend.Tensor usage, etc.).
August 2025
July 2025
1 Commits • 1 Features
Jul 1, 2025Monthly summary for 2025-07 focusing on business value and technical achievements in google/meridian.
July 2025
1 Commits • 1 Features
Jul 1, 2025Monthly summary for 2025-07 focusing on business value and technical achievements in google/meridian.
April 2025
12 Commits • 3 Features
Apr 1, 2025April 2025 monthly summary focused on delivering richer channel insights, expanding organic media analysis, and ensuring release hygiene for Meridian. The work emphasized business value through time-aware visualizations, cross-channel comparisons, and maintainable release processes.
12 Commits • 3 Features
Apr 1, 2025April 2025 monthly summary focused on delivering richer channel insights, expanding organic media analysis, and ensuring release hygiene for Meridian. The work emphasized business value through time-aware visualizations, cross-channel comparisons, and maintainable release processes.
April 2025
March 2025
5 Commits • 2 Features
Mar 1, 2025March 2025 — google/meridian: Implemented data validation and integrity improvements, enhanced analytics capabilities, and improved visualization robustness. Focus areas included data integrity for geometry and coordinates, time-aware metrics for contribution analytics, and responsive Vega charts to fit dynamic containers. These changes increase reliability of data processing, enable time-based insights, and improve visualization UX for end users and business stakeholders.
March 2025
5 Commits • 2 Features
Mar 1, 2025March 2025 — google/meridian: Implemented data validation and integrity improvements, enhanced analytics capabilities, and improved visualization robustness. Focus areas included data integrity for geometry and coordinates, time-aware metrics for contribution analytics, and responsive Vega charts to fit dynamic containers. These changes increase reliability of data processing, enable time-based insights, and improve visualization UX for end users and business stakeholders.
February 2025
1 Commits
Feb 1, 2025February 2025 monthly summary focusing on bug fixes and stability improvements for google/meridian. Key contributions include addressing a critical edge-case in Budget Optimizer and strengthening test coverage, delivering business value through more reliable spend analytics.
1 Commits
Feb 1, 2025February 2025 monthly summary focusing on bug fixes and stability improvements for google/meridian. Key contributions include addressing a critical edge-case in Budget Optimizer and strengthening test coverage, delivering business value through more reliable spend analytics.
February 2025
January 2025
1 Commits
Jan 1, 2025January 2025 monthly summary focused on stabilizing national model evaluation in google/meridian by fixing a holdout filtering index bug, improving 1D time indexing handling, and expanding test coverage. No new features shipped this month; main work centered on bug fix with direct business value in model reliability and data integrity.
January 2025
1 Commits
Jan 1, 2025January 2025 monthly summary focused on stabilizing national model evaluation in google/meridian by fixing a holdout filtering index bug, improving 1D time indexing handling, and expanding test coverage. No new features shipped this month; main work centered on bug fix with direct business value in model reliability and data integrity.
December 2024
6 Commits • 2 Features
Dec 1, 2024December 2024 monthly summary for google/meridian focusing on delivering end-to-end data ingestion and analysis capabilities, stabilizing data integrity, and enabling geospatial-temporal evaluation at scale.
6 Commits • 2 Features
Dec 1, 2024December 2024 monthly summary for google/meridian focusing on delivering end-to-end data ingestion and analysis capabilities, stabilizing data integrity, and enabling geospatial-temporal evaluation at scale.
December 2024
Activity
Loading activity data...
Quality Metrics
Correctness94.4%
Maintainability91.0%
Architecture91.4%
Performance86.0%
AI Usage23.0%
Skills & Technologies
Programming Languages
HTMLJAXJavaScriptMarkdownPythonSQLTensorFlowYAMLproto
Technical Skills
API DesignAPI IntegrationAbstraction LayerAltairBackend DevelopmentBackend IntegrationCI/CDCode AbstractionCode FormattingCode RefactoringConditional LogicConfigurationData AnalysisData EngineeringData Modeling
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline