Random Walk

Not 10 years ago, most doctors agreed that estrogen supplements for post-menopausal women reduced the risk of heart attacks. Millions were paying extravagantly for “hormone replacement therapy”, and drug companies were making a killing. However, a comprehensive study conducted by the Women’s Health Initiative was stopped early, in 2002, because the dangers to healthy women taking estrogen were deemed excessive. Estrogen therapy, it turned out, actually increased the risk of heart attack, strokes, and breast cancer. The medical community was shocked. The Annals of Internal Medicine ran an editorial “How Could We Have Been So Wrong?” The National Institutes of Health hosted a special seminar on “methodology” and “medical evidence”.

In Aleksandr Solzhenitsyn’s novel, The First Circle, originally written in the 1950s, Soviet diplomat Innokenty Volodin makes an ill-advised phone call outside a Metro station.

Last year, the New York Times reported that UPS managed to save 3 million gallons of gas in 2006 by altering the routes of delivery trucks to avoid left turns. According to the article, the company uses software called “package flow” to map out daily routes for drivers. Clearly, the method or “algorithm” this software employs to design efficient routes has sizeable economic (and greenhouse gas) consequences. And, not only is it far from perfect, but the general routing problem is so difficult that, well, if in the course of reading this article you happen upon an efficient solution, you will become immediately famous, at least among computer scientists.