WPO Stats is the definitive collection of web performance case studies, curated by industry leaders Tammy Everts and Tim Kadlec. With 50+ documented experiments from companies like Amazon, Walmart, Rakuten, and Zalando, it provides the hard data needed to make the business case for performance optimization.

The collection is filterable by business metric—revenue, conversions, bounce rate, engagement—making it easy to find relevant proof points. Essential reading for anyone needing to justify performance investments to stakeholders.

Walmart saw up to a 2% increase in conversions for every 1 second of improvement in load time. Every 100ms improvement resulted in up to a 1% increase in revenue.