Intuitively we know that humans are relatively unpredictable, right? It turns out there is quite a gap between our intuition and what scientists are finding out about human dynamics.

The recent paper “Limits of Predictability in Human Mobility” published February 19, 2010 in Science asks “What is the role of randomness in human behavior and to what degree are individual human actions predictable?”

The research team focused on the movements of 45,000 anonymous mobile phone users. User mobility was analyzed using 3 months data collect by mobile phone carriers.

They found that most people stayed in a relatively small neighborhood within about an half a mile (1 km) to 6 miles (10 km) during their daily activities. Another much smaller population was seen to regularly travel much greater distances. The research team expected that the predictability of where these people would go would be much less than those who traveled much smaller distances. They were surprised to find that predictability was about equal across all 45,000 people at about 93% potential predictability. In fact, this number held up across every demographic breakdown they tried.

The measure used defined potential predictability or, in other words, the fundamental limit for each individual’s predictability. That means they found that where people go is 93% predictable in principle. It would be interesting to see to what extent computer algorithms tracking mobility could realize this in practice.