Profit over Proxies: A Scalable Bayesian Decision Framework for Optimizing Multi-Variant Online Experiments
This work addresses the need for profit-driven decision-making in online experiments for businesses, though it is incremental as it builds on existing Bayesian methods.
The paper tackles the problems of flawed heuristics and proxy metrics in online experiments by introducing a Bayesian decision framework for profit optimization, which successfully avoids revenue traps and terminates futile experiments early while maintaining statistical integrity.
Online controlled experiments (A/B tests) are fundamental to data-driven decision-making in the digital economy. However, their real-world application is frequently compromised by two critical shortcomings: the use of statistically flawed heuristics like "p-value peeking", which inflates false positive rates, and an over-reliance on proxy metrics like conversion rates, which can lead to decisions that inadvertently harm core business profitability. This paper addresses these challenges by introducing a comprehensive and scalable Bayesian decision framework designed for profit optimization in multi-variant (A/B/n) experiments. We propose a hierarchical Bayesian model that simultaneously estimates the probability of conversion (using a Beta-Bernoulli model) and the monetary value of that conversion (using a robust Bayesian model for the mean transaction value). Building on this, we employ a decision-theoretic stopping rule based on Expected Loss, enabling experiments to be concluded not only when a superior variant is identified but also when it becomes clear that no variant offers a practically significant improvement (stopping for futility). The framework successfully navigates "revenue traps" where a variant with a higher conversion rate would have resulted in a net financial loss, correctly terminates futile experiments early to conserve resources, and maintains strict statistical integrity throughout the monitoring process. Ultimately, this work provides a practical and principled methodology for organizations to move beyond simple A/B testing towards a mature, profit-driven experimentation culture, ensuring that statistical conclusions translate directly to strategic business value.