Beyond A/B Test : Speeding up Airbnb Search Ranking Experimentation through Interleaving

Introduction of Airbnb interleaving experimentation framework, usage and approaches to address challenges in our unique business

Qing Zhang
11 min readintermediate
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Overview

The article discusses the implementation of an interleaving framework at Airbnb to enhance search ranking experimentation. This method allows for faster and more efficient testing compared to traditional A/B testing, achieving a 50x speedup in algorithm iteration while maintaining high reliability and correlation with A/B test results.

What You'll Learn

1

How to implement interleaving for search ranking experiments

2

Why interleaving improves experimentation speed and sensitivity

3

When to use competitive pairs for measuring user preferences

Key Questions Answered

How does interleaving differ from traditional A/B testing?
Interleaving blends search results from both control and treatment groups, allowing the same user to see results from both rankers. This direct comparison enhances the evaluation of the treatment ranker's impact, unlike traditional A/B testing where users are split into separate groups.
What are the benefits of using interleaving in search ranking?
Interleaving provides a 50x speedup in experimentation, enabling faster iterations on search ranking algorithms. It also demonstrates high agreement with traditional A/B tests, confirming its reliability and robustness in measuring user preferences.
What challenges were faced in implementing the interleaving framework?
Challenges included extending the existing A/B test framework to support interleaving with minimal overhead for ML engineers and adapting the search infrastructure designed for single request searches to accommodate the new functionality.
How is attribution handled in the interleaving framework?
Attribution in the interleaving framework accounts for multiple clicks on listings across different rankers, allowing for flexible credit assignment based on user interactions, which is crucial for accurately measuring booking conversions.

Key Statistics & Figures

Sensitivity improvement
50x
Achieved in the development of Airbnb's search ranking algorithm through the interleaving framework.
Agreement with A/B tests
82%
The consistency between interleaving results and traditional A/B test outcomes.
Traffic allocation for interleaving experiments
6%
Each interleaving experiment utilizes 6% of the regular A/B test traffic.

Key Actionable Insights

1
Implementing interleaving can drastically reduce the time needed for search ranking experiments.
By integrating interleaving into your experimentation process, you can test multiple variations quickly, allowing for rapid identification of effective strategies and improvements in user experience.
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Utilizing competitive pairs can enhance the precision of user preference measurements.
This method minimizes position bias and focuses on direct comparisons, leading to more reliable insights into user behavior and preferences.
3
Consider the specific context of your ranking algorithms when applying interleaving.
Some rankers may involve set-level optimizations that could lead to inaccuracies with interleaving, so it's essential to evaluate its applicability on a case-by-case basis.

Common Pitfalls

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Assuming interleaving will work effectively for all ranking algorithms without evaluation.
Interleaving may not be suitable for rankers that rely on set-level optimizations, leading to inaccurate results. It's crucial to assess the specific characteristics of each ranker before applying interleaving.