What Is the Lindy Effect? Taleb's Test of Time

The Lindy effect is the observation that for non-perishable things — ideas, books, institutions, technologies, practices — the expected remaining lifespan increases with age. The longer something has already survived, the longer it is likely to continue surviving.

Where It Comes From

The term originated with the observation that the lifespan of a Broadway show's run could be predicted by how long it had already run — the Lindy's delicatessen in New York was where comedians would discuss this. Taleb formalized and extended it in the Incerto series and The Bed of Procrustes as a general heuristic for evaluating the reliability of ideas, practices, and knowledge.

How It Works in Practice

A book that has been read and cited for 500 years has survived sustained scrutiny and changing contexts. The odds are it contains something durable. A book published last year has not yet been tested. The Lindy effect says: weight the 500-year-old book more heavily, by default, even if the new book is more sophisticated.

Quick example: Classical wisdom on diet (eat mostly unprocessed whole foods, fast occasionally, don't eat things your great-grandmother wouldn't recognize) has the Lindy advantage — humans ate this way for millennia. The latest low-fat or keto protocol is a recent innovation with no long-run track record. Lindy thinking weights the former.

"A good book gets better on the second reading. A great book on the third. Any book not worth rereading isn't worth reading."

This is Lindy applied to individual books: the great books improve with each reading, which means they contain more than you could extract in one pass. Their longevity is evidence of depth.

Why It Matters

The Lindy effect is a subtractive epistemological tool: rather than evaluating new ideas on their merits alone (which requires expertise you may not have), ask how long the competing alternatives have survived.

Learn More

For the full framework on reliable knowledge versus unreliable forecasting, read The Bed of Procrustes Explained.