"Virtuous circle"

[Paul McFedries]

Not to be nitpicky, but I just checked the text of Greenspan's speech,
and he actually used the term "virtuous cycle":

     To be sure, there is also a virtuous cycle at play here.
     A whole new set of profitable investments raises
     productivity, which for a time raises profits -- spurring
     further investment and consumption.

This is not quite as popular as "virtuous circle," with only 434 L-N
citations for 1999. Note, too (insert nod to Fred Shapiro here) that the
OED doesn't have virtuous cycle (or even vicious cycle, for that matter;
it does have vicious circle and vicious spiral).

The earliest L-N citation is from Business Week, February 12, 1979:

     They call it the "virtuous cycle," one in which a series
     of sound economic policies sets off a chain of events in
     which improved economic performance produces sound
     currencies. This in turn helps to improve economic
     performance further.

Paul
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