Lindy effect

The Lindy effect (also known as Lindy's law) is a theorized phenomenon by which the future life expectancy of some non-perishable thing, like a technology or an idea, is proportional to its current age. Thus, the Lindy effect proposes the longer a period something has survived to exist or be used in the present, the longer its remaining life expectancy. Longevity is a resistance to change, obsolescence, or competition, and greater odds of continued existence into the future. Where the Lindy effect applies, mortality rate decreases with time. Mathematically, the Lindy effect corresponds to lifetimes following a Pareto probability distribution. The concept is named after Lindy's delicatessen in New York City, where the concept was informally theorized by comedians: a show running only two weeks would be expected to last another two weeks, while a show that has lasted two years could expect a further two-year run. The Lindy effect has subsequently been theorized by mathematicians and statisticians. Nassim Nicholas Taleb has expressed the Lindy effect in terms of "distance from an absorbing barrier". The Lindy effect applies to non-perishable items, like books, those that do not have an "unavoidable expiration date". For example, human beings are perishable: the life expectancy at birth in developed countries is about 80 years. So the Lindy effect does not apply to individual human lifespan: all else being equal, it is less likely for a 10-year-old human to die within the next year than for a 100-year-old, while the Lindy effect would predict the opposite.