Calibrating your probability estimates of world events: Russia vs Ukraine, 6 months later.

Some of the com­ments on the link by James_Miller ex­actly six months ago pro­vided very spe­cific es­ti­mates of how the events might turn out:


  • The odds of Rus­sian in­ter­ven­ing mil­i­tar­ily = 40%.

  • The odds of the Rus­si­ans los­ing the con­ven­tional bat­tle (per­haps be­cause of NATO in­ter­ven­tion) con­di­tional on them en­ter­ing = 30%.

  • The odds of the Rus­si­ans re­sort­ing to nu­clear weapons con­di­tional on them los­ing the con­ven­tional bat­tle = 20%.


“Rus­si­ans in­ter­ven­ing mil­i­tar­ily” could be any­thing from pos­tur­ing to weapon ship­ments to a sur­gi­cal strike to a Cze­choslo­vakia-style tank-roll or Afghanistan in­va­sion. My guess that the odds of the lat­ter is be­low 5%.

A bet be­tween James_Miller and solip­sist:

I will bet you $20 U.S. (mine) vs $100 (yours) that Rus­sian tanks will be in­volved in com­bat in the Ukraine within 60 days. So in 60 days I will pay you $20 if I lose the bet, but you pay me $100 if I win.

While it is hard to do any mean­ingful cal­ibra­tion based on a sin­gle event, there must be les­sons to learn from it. Given that Rus­sian ar­mored columns are said to cap­ture key Ukrainian towns to­day, the first part of James_Miller’s pre­dic­tion has come true, even if it took 3 times longer than he es­ti­mated.

Note that even the most pes­simistic per­son in that con­ver­sa­tion (James) was prob­a­bly too op­ti­mistic. My es­ti­mate of 5% ap­pears way too low in ret­ro­spect, and I would prob­a­bly bump it to 50% for a similar event in the fu­ture.

Now, given that the first pre­dic­tion came true, how would one reeval­u­ate the odds of the two fur­ther es­ca­la­tions he listed? I still feel that there is no way there will be a “con­ven­tional bat­tle” be­tween Rus­sia and NATO, but hav­ing just been proven wrong makes me doubt my as­sump­tions. If any­thing, maybe I should give more weight to what James_Miller (or at least Dan Car­lin) has to say on the is­sue. And if I had any skin in the game, I would prob­a­bly be even more cau­tious.