America’s Cup Comeback not quite THAT Improbable

photo: USA Today

People say that the Oracle Team USA boat came back from being down 8:1 to win 8 straight and successfully defend the AC.  Actually, although the score was 8:1, the wins were “only” 8:3 in favor of Emirates Team New Zealand.  Oracle was docked 2 points for irregularities in the lead-in series sailed in 45’ cats.  The difference between 8:1 and 8:3 is dramatic when you compare the odds of losing team (Oracle) winning the next 8 straight.  

Trailing 8:3, the odds of Oracle winning the next race, race 12, was 3 in 11 (or 27%) because they had won 3 of the previous 11 races.  This is significantly better than the 11% odds they would have faced if they had won only 1 of the previous 9 races (i.e., really stood at 8:1).  No fancy Sabermetrics-on-water here, just common sense.  The next race, number 13, reached only because Oracle won the do-or-die race 10, was a little better, at 33%, and so on.  Oddly, due to the penalty, what began as a "best of 17", so first to 9 wins, became a 19 race series because ETNZ won 8 and Oracle won 11.  

The bottom line is that trailing 8:3 the losing team has about a 1:1,000 chance of winning the next 8 straight, whereas trailing 8:1 the odds are closer to 1 in a million.  This ignores the improvements the Oracle team made in their boat, which made their ultimate victory much more probable. The comeback was a truly remarkable, historical achievement by any measure.