Second Opinion for Google Optimize is a Chrome extension developed by Jorge Alonso. This free tool is designed to provide users with a second opinion on their Google Optimize A/B experiments. The extension fetches experiment data from Google Optimize and calculates significance using other well-known statistical significance calculation sites, namely ABTestGuide and Evan Miller's.

With Second Opinion, users can easily compare the calculations from different sites side by side. The extension embeds iframes on Google Optimize's page, allowing users to refresh the calculations by simply clicking on the extension button whenever an experiment is refreshed.

It's important to note that Second Opinion only works for A/B tests and does not support multivariate experiments. If you're looking for a reliable tool to validate your Google Optimize A/B experiment results, Second Opinion for Google Optimize provides an additional perspective and enhances your decision-making process.