Experimental Design in Two-Sided Platforms: An Analysis of Bias

By Ramesh JohariHannah LiInessa LiskovichGabriel Weintraub
Management Science
October2022 Vol. 68 Issue 10 Pages 7065–7791.

[Part of the thesis awarded the 2023 George B. Dantzig Dissertation Award; Winner of 2023 MSOM SIG Best Paper Award in Service Management; Finalist 2025 Management Science Best Paper in OM Award; 2nd place 2021 RMP Jeff McGill Student Paper Award]

We develop an analytical framework to study experimental design in two-sided marketplaces. Many of these experiments exhibit interference, where an intervention applied to one market participant influences the behavior of another participant. This interference leads to biased estimates of the treatment effect of the intervention. We develop a stochastic market model and associated mean field limit to capture dynamics in such experiments, and use our model to investigate how the performance of different designs and estimators is affected by marketplace interference effects. Platforms typically use two common experimental designs: demand-side (“customer”) randomization (CR) and supply-side (“listing”) randomization (LR), along with their associated estimators. We show that good experimental design depends on market balance: in highly demand-constrained markets, CR is unbiased, while LR is biased; conversely, in highly supply-constrained markets, LR is unbiased, while CR is biased. We also introduce and study a novel experimental design based on two-sided randomization (TSR) where both customers and listings are randomized to treatment and control. We show that appropriate choices of TSR designs can be unbiased in both extremes of market balance, while yielding relatively low bias in intermediate regimes of market balance.