Tuesday, September 15, 2009

Bermuda Bowl Analysis

I have done some analysis on the performance of each pair in the Bermuda Bowl final.

The method is based on assigning each pair an IMP score on each board reflecting the result they deserve to get relative to an error-free world class pair. In most cases I did this independently of the actual result so a minus would be assigned for missing a good game regardless of whether the game made in practice.

There is also a luck score for each board which is not assigned directly and is just the difference between the accumulated 'deserved' IMPs and the actual IMPs that changed hands. The total of this over the 128 boards was only 6 IMPs (in favour of the USA) so luck had very little effect overall though there were big numbers on individual hands.

Here is an example of the methodology. On board 2, Lauria/Versace were -200 in 4C and Nickell/Katz were -100 in 3NT. Based on the N/S cards I judged that 4C will normally make and 3NT will be down one. However, on the actual lie 4C is down one (though it can make double dummy) and 3NT is down two. Accordingly I penalized Lauria/Versace 3 IMPs for an unnecessary extra undertrick, Nickell/Katz 6 IMPS as they 'deserved' -100 against +130, and Fantoni/Nunes 3 IMPs for letting Nickell/Katz get out for -100 instead of -200. Since the USA gained 3 IMPs and the deserved IMPS totalled zero, this counted as 3 IMPs in the luck column for the USA. The luck here is in the fact that an unusually bad lie converted a possible partscore swing against the USA into just a question of undertricks.

The totals were:
PairNum BoardsAvg. IMPs per board
Meckstroth/Rodwell128-1.15
Hamman/Zia80-1.59
Nickell/Katz48-2.10
Lauria/Versace96-1.50
Fantoni/Nunes80-1.21
Sementa/Dubion80-1.95

As you can see, Meckstroth/Rodwell did slightly better than Fantoni/Nunes, while Lauria/Versace did slightly better than Hamman/Zia. Nickell/Katz and Sementa/Dubion were easily the weakest pairs on their respective teams.

It appears that the choice of lineups accounts for almost the entire winning margin. The US played their best pair for every board and their weakest pair for the minimium number. If Italy had done the same, by my reckoning they would have closed the gap from 36 IMPs to 7 IMPs - less than the carryover.

The calculations are in this Excel spreadsheet. I am certainly open to any of this being disputed as there may be excellent reasons for the bids and plays chosen that I am unaware of.

The play records are located here.

1 comment:

Paul Gipson said...

The Imp Chimp has also analysed the boards, albeit without summarising.

My subjective view agrees with your table. Meckwell clearly ahead and Fantunes the best Italian pair.