[1][2] The lower the number, the closer a person is to Erdős and Bacon, which reflects a small world phenomenon in academia and entertainment.
[3] To have a defined Erdős–Bacon number, it is necessary to have both appeared in a film and co-authored an academic paper, although this in and of itself is not sufficient as one's co-authors must have a known chain leading to Paul Erdős, and one's film must have actors eventually leading to Kevin Bacon.
[4] Like Kleitman, mathematician Bruce Reznick has co-authored a paper with Erdős[5] and has a Bacon number of 2, via Roddy McDowall in the film Pretty Maids All in a Row where he appeared as an extra, giving him an Erdős–Bacon number of 3 as well.
Metropolis and Richard Feynman both worked on the Manhattan Project at Los Alamos Laboratory.
While an undergraduate at the University of California, Los Angeles, McKellar coauthored a mathematics paper[14] with Lincoln Chayes, who via his wife Jennifer Tour Chayes[15] has an Erdős number of 3, giving McKellar one of 4.
Firth is credited as co-author of a neuroscience paper, "Political Orientations Are Correlated with Brain Structure in Young Adults",[23] after he suggested on BBC Radio 4 that such a study could be done.