  In this paper we provide compelling evidence of cyclical mean reversion and
multiperiod stock return predictability over horizons of about 30 years with a
half-life of about 15 years. This implies that the US stock market follows a
long-term rhythm where a period of above average returns tends to be followed
by a period of below average returns. We demonstrate that this long-term stock
market rhythm moves in lockstep with corresponding long-term economic, social,
and political rhythms in the US. Assuming that the past relationship between
these rhythms will hold unaltered in the future, we provide the medium to
long-term stock market outlook.
