By Leon Yin, Adrianne Jeffries, and Surya Mattu:

In early 2018, several advocacy groups noticed a drop in open rates for subscribers with Gmail domains. They said this had a negative impact on calls to action and donations. 

Using data sent to us by three of these advocacy groups as well as Change.org, a for-profit company that hosts petitions for political causes, we confirmed there was a lasting decrease in open rates unique to subscribers using Gmail.