[Tloewald]

There is nothing to suggest that the second cohort only includes failures, and bear in mind that many people -- having failed -- won't try a second time -- and if they've learned anything, it will be the people who figure out they're never going to succeed who drop out. Without knowing the probability that someone who succeeds vs. fails will try again there's simply no way to tell.

Anecdotally, it's very common for entrepreneurs to start a business, wait until it's up and running, sell it, and start over. This applies both in high-tech and more prosaic areas like restaurants and gas stations. I imagine that first-time successes are very likely to try again.

[Smirnoff]

Actually, the post says it explicitly that this 20% includes only failures. --> "... entrepreneurs who previously failed have a 20% chance of succeeding."

[Tloewald]

But what chance of success do entrepreneurs who previously succeeded have?

[Smirnoff]

This statistic wasn't there but one could imagine that it would be higher than 20%. Also, keep in mind that success is a subjective term -- for some people it's when you make $1M, break-even or get acquihired, for others it's at least $100M or $1B.