… What exactly is a “random walk”? And why would it matter to ordinary people following the campaign? Answering these questions produces two simple but important lessons for reading election polls.
A random walk means this: It is very hard to predict the future movement in some quantity from its present value. Economists often argue that prices follow a random walk: The fact that a T-shirt costs $10 today doesn’t tell you whether it will cost more or less tomorrow.
So how does this apply to presidential polls? CONT.
Robert Erikson (Columbia) & Christopher Wlezien (U. of Texas), The Monkey Cage