The first episode was transmitted at 5:16p.m. on Saturday 23 November 1963. The assassination of American President John F. Kennedy the previous day overshadowed the launch of a new television series; as a result, the first episode was repeated a week later, on 30 November, preceding the second episode. The first episode was watched by 4.4 million viewers (9.1% of the viewing audience), and it received a score of 63 on the Appreciation Index; the repeat of the first episode reached a larger audience of six million viewers. Across its four episodes, "An Unearthly Child" was watched by an average of 6 million (12.3% of potential viewers). Episodes 2–4 achieved ratings of 5.9, 6.9 and 5.4 million viewers, respectively. Mark Bould suggests that a disappointing audience reaction and high production costs prompted the BBC's chief of programmes to cancel the series until the Daleks, introduced in the second serial in December 1963, were immediately popular with viewers.