Lindy effect

The Lindy effect is an idea that the future life expectancy of some non-perishable things like a technology or an idea is proportional to their current age, so that every additional period of survival implies a longer remaining life expectancy. Where the Lindy effect applies, mortality rate decreases with time. In contrast, living creatures and mechanical things follow a bathtub curve where, after "childhood", the mortality rate increases with time. Because life expectancy is probabilistically derived, a thing may become extinct before its "expected" survival. In other words, one needs to gauge both the age and "health" of the thing to determine continued survival.

The origin of the term and idea can be traced to Albert Goldman and a 1964 article he had written in The New Republic titled "Lindy's Law'. In it he stated that "the future career expectations of a television comedian is proportional to the total amount of his past exposure on the medium". The term Lindy refers to the NY Deli Lindy's where comedians "foregather every night at Lindy's, where... they conduct post-mortems on recent show biz "action".Benoit Mandelbrot formally coined the term Lindy Effect in his 1984 Book The Fractal Geometry of Nature. Mandelbrot expressed mathematically that for certain things bounded by the life of the producer, like human promise, future life expectancy is proportional to the past. He references Lindy's Law and a parable of the young poets’ cemetery and then applies to researchers and their publications: "However long a person's past collected works, it will on the average continue for an equal additional amount. When it eventually stops, it breaks off at precisely half of its promise."

Nassim Taleb furthered the idea in the The Black Swan: The Impact of the Highly Improbable by extending to a certain class of nonperishables where life expectancy can be expressed as power laws.

With human projects and ventures we have another story. These are often scalable, as I said in Chapter 3. With scalable variables… you will witness the exact opposite effect. Let's say a project is expected to terminate in 79 days, the same expectation in days as the newborn female has in years. On the 79th day, if the project is not finished, it will be expected to take another 25 days to complete. But on the 90th day, if the project is still not completed, it should have about 58 days to go. On the 100th, it should have 89 days to go. On the 119th, it should have an extra 149 days. On day 600, if the project is not done, you will be expected to need an extra 1,590 days. As you see, the longer you wait, the longer you will be expected to wait

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