Daniel Kahneman, a senior scholar at Princeton University and a winner of the Nobel Prize in Economic Sciences, Dan Lovallo, a professor of business strategy at the University of Sydney, and Olivier Sibony, a director in the Paris office of McKinsey & Company, write about how dangerous assumptions can creep into every strategic proposal â€" and how you can avoid them.This article was first published in the June 2011 issue of Harvard Business Review. Before You Make That Big Decision… (Harvard Business Review)