Google announced on Tuesday a new open source tool that can help data analysts decide if changes to products or policies resulted in measurable change, or if the change would have happened anyway. The tool, called CausalImpact, is a package for the R statistical computing software, and Google details it in a blog post.

According to blog post author Kay H. Brodersen, [company]Google[/company] uses the tool — created it, in fact — primarily for quantifying the effectiveness of AdWords campaigns. However, he noted, the same method could be used to gauge everything from whether adding a new feature caused an increase in app downloads to questions involving events in medical, social or political science.

Here’s how Brodersen describes CausalImpact in the blog, first at a high level and then in some more detail. The blog post has a deeper explanation of the package, as well as instructions for installing it via GitHub:

“In practice, estimating…