Interestingly enough, both Hans Rosling and Ken Robinson began their rather prolific careers as TED speakers at the same TED event, <a href="https://www.ted.com/about/conferences/past-teds/ted2006" target="_blank">TED2006</a>, where they spoke alongside 44 other lecturers. One of them was <a href="https://helenfisher.com/" target="_blank">Helen Fisher</a>, a prominent anthropologist and international bestseller, who also went on to speak two more times with TED by the time of this data's collection. These three speakers are ideal for longitudinal comparison due to the varying number of their subsequent speeches and their beginnings at the same event.