In episode 331 of Semantic Mastery's weekly Hump Day Hangouts, one participant asked if the team tests titles for higher CTR.
The exact question was:
Hi guys: You started very early today. 1 hour early. didn't prepare questions but what comes in my mind: 1) Do you test titles for higher CTR? How to test the title without giving up rankings and with increasing the CTR. The CTR I get is shit for the impressions I get.