Recently, we also learned about the U.S. Economic Policy Uncertainty Index, which is compiled by economists Steven Davis of the University of Chicago and Scott Baker and Nicholas Bloom of Stanford.

FORBES: Contrarian Buy Signals

Three economists, Stanford University's Nicholas Bloom and Scott Baker and the University of Chicago's Steven Davis, have done invaluable work measuring the level of policy uncertainty over the past few decades.

WSJ: Bill McNabb: Uncertainty Is the Enemy of Recovery