Imbalance Detection in Online Experiments via Permutation Tests

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Solution Overview

Problem

Existing experimentation methods, such as A/B testing, often face challenges in detecting imbalances in user populations, leading to unreliable and resource-intensive results.

Innovation Solution

The proposed solution involves a resource-efficient technique for automatically detecting imbalances in experimentation by using permutation tests applied to contingency tables, which can handle large data sets and run independently in parallel, leveraging distributed computing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If permutation tests are applied to raw data points directly, then measurement precision improves, but computing resource consumption increases significantly

Engineering Contradiction:
Improveimbalance detection accuracyVSAvoidcomputing resource consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential features needed for imbalance detection by applying permutation tests to contingency tables derived from aggregated experiment data, rather than processing all raw data points. This extraction approach maintains detection precision while significantly reducing computational resource consumption by working with summarized statistics instead of individual data points.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If permutation tests are run in parallel across multiple experiments, then productivity improves, but device complexity increases

Engineering Contradiction:
Improveexperiment processing speedVSAvoidparallel processing infrastructure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the overall experimentation process into independent units that can be processed in parallel. Each experiment's contingency table analysis is divided into separate permutation test tasks that can execute concurrently across multiple processing units. This segmentation enables scalable parallel processing that increases productivity while managing device complexity through modular task design.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS20250147871A1Imbalance detection in online experiments
Publication Date: 2025.05.08 ETSY INC
  • US20250147871A1 patent drawing
  • US20250147871A1 patent drawing
  • US20250147871A1 patent drawing

AI summary

Methods, systems, and apparatus, including computer programs encoded on computer-storage media, for imbalance detection in online experiments. In some implementations, a method includes obtaining user information indicating a first set of devices assigned a first version of a service and a second set of devices assigned a second version of the service in a multivariate testing framework; generating alternative samplings of devices; generating a threshold for detecting imbalance using the alternative samplings of devices, a generated expected first set of devices, and a generated expected second set of devices; detecting an imbalance using the obtained user information indicating the first set of devices, the second set of devices, and the generated threshold; and implementing a corrective action to mitigate the detected imbalance in the multivariate testing framework.