摘要：This paper shows that, with (partial) irreversibility, higher uncertainty
reduces the impact effect of demand shocks on investment. Uncertainty increases
real option values making firms more cautious when investing or disinvesting.
This is confirmed both numerically for a model with a rich mix of adjustment
costs, time-varying uncertainty, and aggregation over investment decisions and
time, and also empirically for a panel of manufacturing firms. These cautionary
effects of uncertainty are large - going from the lower quartile to the upper
quartile of the uncertainty distribution typically halves the first year
investment response to demand shocks. This implies the responsiveness of firms
to any given policy stimulus may be much lower in periods of high uncertainty,
such as after major shocks like OPEC I and 9/11
关键词：Investment, uncertainty, real options, panel data
