We are now in one of the longest expansions on record. The recession that preceded that expansion was one of the worst in history. Are those two facts related? Some economists suggest they are, while others suggest it’s the other way around: Longer expansions lead to more severe recessions. We assess the evidence for these two hypotheses. We find clear evidence for the former and little for the latter. Deeper recessions are often followed by stronger recoveries, while longer and stronger expansions are not followed by deeper recessions.