Etsy Engineering9 min readNov 25, 2025

Reducing experiment duration with predicted control variates

In 2021, we published a blog post titled “Increasing experimentation accuracy and speed by using control variates,” describing how we reduce the variance of metrics using CUPED in our experimentation

Performance

CUPEDExperimentationControl VariatesExperimental Design

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Making Ads Count: Using MMoE and Auxiliary Tasks to Better Connect Buyers & Sellers

When buyers search on Etsy, they need to quickly and easily find the perfect item. At the same time, sellers need to be confident their unique products are...

Etsy Engineering11 min18d ago

Migrating Etsy’s database sharding to Vitess

Etsy has maintained a sharded MySQL architecture since around 2010. This database cluster contains most of Etsy’s online data and is made up of ~1,000 tables...

Distributed SystemsDatabases

MySQLVitessKubernetesDatabase ShardingLarge Scale SystemMicroservicesDatabase Architecture

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Reducing experiment duration with predicted control variates

Making Ads Count: Using MMoE and Auxiliary Tasks to Better Connect Buyers & Sellers

Migrating Etsy’s database sharding to Vitess

How Etsy Uses LLMs to Improve Search Relevance