NBA Finals Chicago over Seattle with 85-90% certainty After 6 G's: Chicago wins 4-2, which was the most likely result. Third Round Chicago over Orlando with 91% certainty After 4 G's: Chi beats Orl 4-0 Seattle over Utah with 85-87% certainty After 7 G's: Sea beats Uta 4-3 Second Round Chicago over New York with 99% certainty After 5 G's: Chicago beats NY 4-1 Orlando over Atlanta with 92% certainty After 5 G: Orlando beats Atlanta 4-1 Seattle over Houston with 93% certainty After 4 G's: Seattle beats Hou 4-0 San Antonio over Utah with 66% certainty After 4 G's: Utah beats SA 4-2 First Round Chicago over Miami with 99% certainty After 3 G's: Chicago wins 3-0 Cleveland over New York with 50.4% certainty After 3 G's: New York wins 3-0 Indiana over Atlanta with 70% certainty After 5 G's: Atlanta wins 3-2 Orlando over Detroit with 90% certainty After 3 G's: Orlando wins 3-0 Seattle over Sacramento with 97% certainty After 4 G's: Seattle wins 3-1 LA Lakers over Houston with 64% certainty After 4 G's: Houston wins 3-1 Utah over Portland with 82% certainty After 5 G's: Utah wins 3-2 San Antonio over Phoenix with 89% certainty After 4 G's: San Antonio wins 3-1
I didn't believe the prior probability of Seattle beating Houston, but it did pretty well, if one can say these things about probabilistic events. Houston threw everyone's odds out the window last season, so I'm personally glad their gone this year.
The most likely result of the New York-Chicago matchup was a four game sweep (52%). The next most likely result was Chicago in five games (34%). Not bad. Ho-hum.
New York's sweep of Cleveland in the first round was not a major surprise. Prior to the series, such a result was to be expected 12% of the time.
P(A beats B at A's Home) =
(A's Hm Rec)(1-B's Rd Rec)(Lg Rd Rec)
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[(A's Hm Rec)(1-B's Rd Rec)(Lg Rd Rec)+(1-A's Hm Rec)(B's Rd Rec)(Lg Hm Rec)
A's Hm Rec Team A's Record at Home
B's Rd Rec Team B's Record on the Road
Lg Rd Rec The League Average Winning % on the Road (0.396)
Lg Hm Rec The League Average Winning % at Home (0.604)
This formula comes from Bill James' Baseball Abstract '87
and its theoretical development has apparently been published
somewhere academic, though I honestly
do not know where.
With the above formula and the schedule for each of the playoff series, you can evaluate each team's chances of winning their first round series. There is a bit of combinatorics involved, but it's not too bad. (For those who know statistics: note that I did not do any Bayesian updating of the game probabilities, neither for season records nor for playoff outcomes. There is a straightforward way to do it for the playoffs, but I'm not convinced that the straightforward way is actually right.)
The results of this method are shown below:
Second Round Chicago over New York with 99% certainty Seattle over Houston with 93% certainty First Round Chicago over Miami with 99% certainty Cleveland over New York with 50.4% certainty Indiana over Atlanta with 70% certainty Orlando over Detroit with 90% certainty Seattle over Sacramento with 97% certainty LA Lakers over Houston with 64% certainty Utah over Portland with 82% certainty San Antonio over Phoenix with 89% certainty
It is important to remark that these estimates are really just base approximations based upon season records. They do not account for Reggie Miller missing from Indiana, Seattle's tendency to choke (Denver had a 1% chance two years ago against them), or Houston's high variance style increasing their odds as underdogs. Accounting for these missing pieces involves a considerable amount of work.
Finally, you can carry out these calculations throughout the playoffs and you find that the Chicago Bulls have at least a 75% chance of winning it all -- they are 1-3 favorites. That is pretty close to what the oddsmakers have been saying, so the method appears to be reasonable, despite its limiting assumptions. For those with more spare time than I have, they can figure out all the combinatorics involved and calculate the probabilities of winning the Championship for all the teams.