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Reducing Marketplace Interference Bias Via Shadow Prices

Ido Bright, Arthur Delarue, Ilan Lobel

arXiv 4 May 2022 · Mathematics — Optimization · publishedManagement Science (2024) · 9 citations (OpenAlex)

arXiv:2205.02274 · PDF · DOI · OpenAlex · Extracted main text

Abstract

Marketplace companies rely heavily on experimentation when making changes to the design or operation of their platforms. The workhorse of experimentation is the randomized controlled trial (RCT), or A/B test, in which users are randomly assigned to treatment or control groups. However, marketplace interference causes the Stable Unit Treatment Value Assumption (SUTVA) to be violated, leading to bias in the standard RCT metric. In this work, we propose techniques for platforms to run standard RCTs and still obtain meaningful estimates despite the presence of marketplace interference. We specifically consider a generalized matching setting, in which the platform explicitly matches supply with demand via a linear programming algorithm. Our first proposal is for the platform to estimate the value of global treatment and global control via optimization. We prove that this approach is unbiased in the fluid limit. Our second proposal is to compare the average shadow price of the treatment and control groups rather than the total value accrued by each group. We prove that this technique corresponds to the correct first-order approximation (in a Taylor series sense) of the value function of interest even in a finite-size system. We then use this result to prove that, under reasonable assumptions, our estimator is less biased than the RCT estimator. At the heart of our result is the idea that it is relatively easy to model interference in matching-driven marketplaces since, in such markets, the platform mediates the spillover.

Citation extraction

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Most heavily cited references

The works this paper leans on most, across its whole bibliography — not restricted to papers in our corpus. Ranked by composite intensity, which combines how often a work is mentioned, how many sections mention it, and how much of that falls in the main text rather than the appendix.

ReferenceIntensityMentionsSectionsMain text
1Hannah Li, Geng Zhao, Ramesh Johari, and Gabriel Y Weintraub (2022) Interference, bias, and variance in two-sided marketplace experimentation: Guidance for platforms0.64422100%
2Patrick Bajari, Brian Burdick, Guido W Imbens, Lorenzo Masoero, Jame… (2021) Multiple Randomization Designs0.58531100%
3Ramesh Johari, Hannah Li, Inessa Liskovich, and Gabriel Y Weintraub (2022) Experimental Design in Two-Sided Platforms: An Analysis of Bias0.58531100%
4Nicholas Chamandy (2016) Experimentation in a Ridesharing Marketplace0.51121100%
5New York City Taxi and Limousine Commission (2022) Trip record data0.40511100%
6Ravindra K Ahuja, Thomas L Magnanti, and James B Orlin (1993) Network flows: theory, algorithms, and applications, chapter 9, page 2990.40511100%
7Thomas Blake and Dominic Coey (2014) Why Marketplace Experimentation is Harder Than It Seems: The Role of Test-Control Interference0.40511100%
8Iavor Bojinov, David Simchi-Levi, and Jinglong Zhao (2022) Design and Analysis of Switchback Experiments0.40511100%
9Alex Chin (2019) Regression Adjustments for Estimating the Global Treatment Effect in Experiments with Interference0.40511100%
10WG Cochran (1939) Long-Term Agricultural Experiments0.40511100%

Showing the top 10 of 18 scored citations.

Cited by, within the corpus

arXiv econ.EM papers that cite this one, ranked by how heavily they lean on it.

Citing paperIntensityMentionsSections
1Higher-Order Causal Message Passing for Experimentation with Complex Interference0.51121
22501.119960.51121
3Multiple Randomization Designs: Estimation and Inference with Interference0.40511
4Estimating Effects of Long-Term Treatments0.40511
5Tackling Interference Induced by Data Training Loops in A/B Tests: A Weighted Training Approach0.40511
6Can We Validate Counterfactual Estimations in the Presence of General Network Interference?0.40511
7Experimental Design for Matching0.40511
8Validating Causal Message Passing Against Network-Aware Methods on Real Experiments0.40511