Have We Been Doing Control Groups All Wrong?

6sided_dice

To start 2015, we are featuring some “Lost Gems” from 2014 — some great posts that deserved to get wider notice than they did the first time out. Every time we test a new subject line, a new survey question, a new image, a new way-cool-and-so-much-better alternative, we always use a control group. That way, […]