http://www.eecs.harvard.edu/~michaelm/postscripts/handbook2001.pdf http://www.eecs.harvard.edu/~michaelm/postscripts/handbook20... Basically pick-2 allows you

http://www.eecs.harvard.edu/~michaelm/postscripts/handbook2001.pdf http://www.eecs.harvard.edu/~michaelm/postscripts/handbook20... Basically pick-2 allows you to make a mixture of a totally random and optimal choice in cases where you have imperfect information that is much more resilient to the staleness of data than either a random choice or the globally optimum choice.