Talk:Lindy effect

Probability and Humans
The article states "it is very likely for a 70-year-old human to die within the next 70 years, while the Lindy effect would predict these to have equal probability." Shouldn't the probability of death of a 70-year-old be smaller than the 5-year-old's in the presence of the Lindy effect? — Preceding unsigned comment added by 81.155.48.243 (talk) 12:23, 13 June 2022 (UTC)


 * I believe so. Otherwise the effect makes no sense. I came to the talk page to say the same. 2601:14D:4E01:1860:BD0E:E50:ADDE:207F (talk) 21:46, 5 July 2023 (UTC)
 * Your quote left out the first part of the sentence, which (read carefully) should resolve this confusion: it is unlikely for a 5-year-old human to die within the next 5 years, but it is very likely for a 70-year-old human to die within the next 70 years, while the Lindy effect would predict these to have equal probability. (my bolding).
 * Feel free to make suggestions about how to reword the sentence to make it easier for hasty readers to avoid this misunderstanding. But it is correct as written.
 * Regards, HaeB (talk) 04:10, 6 July 2023 (UTC)
 * The current quotation 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. may be misleading, as it implies the entire human lifespan. The Lindy Effect indeed may apply to perishable items, for a period of time, so long as their probability of death is decreasing over time sufficiently to skew the average life expectancy, which may be the case for humans lifespans under certain conditions, or if you consider all of a human being's development (in particular, the fetal period, which is subject to very high miscarriage rates) as part of its lifespan.  See an additional (non-human) example in "Perishable Goods," below.

Perishable Goods
The statement that it applies to non-perishable items does not exclude the possibility that it applies to some perishable items for a period of time. As a simple example, consider a manufacturing line that produces cars. Let 90% of cars fail exactly at the 1 year mark and the remaining 10% of cars last until the 3.5 year mark. The average life expectancy at manufacture is 1 yr * p(fail at 1 yr) + 3.5 yr * p(fail at 3.5 yr) = 1.25 years. For any cars that survive past the 1 year mark, the average life expectancy becomes (3.5 yr - 1 yr) * 100% = 2.5 years, twice what it was at birth. As time moves forward beyond that point, the Lindy effect no longer applies. Another example could be human life expectancy, given sufficiently high infant mortality rates. — Preceding unsigned comment added by 173.73.108.194 (talk) 23:57, 23 April 2024 (UTC)

Comparing 10-year-old to 100-year-old
The usefulness of the phrase "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" seems to be vague, as I'm not sure how to imagine that all else is equal between a 10-year-old and a 100-year-old besides their ages. — Preceding unsigned comment added by 173.73.108.194 (talk) 21:35, 24 April 2024 (UTC)