Have you ever noticed that your score seems to suddenly change on the last round? Ours usually seem to go down!
Firstly, you need to understand how pairs events are scored. It is very simple in principle – On each board your score is compared with everyone else who played the same way round. For every pair you beat you get 2 points, for every pair you draw with you get 1 point and for every pair you lose to you get no points.
An easy example is when 6 pairs have played the board. Your score is compared with the other 5 results and so the maximum score (a ‘top’) is 10 points if you beat everyone else, or 5 points if all the scores are the same. At the end of the event all the scores on each board are added up and your score is given as a percentage of the maximum number of points that you could score. [If you sit out the system allows for this because your maximum score is less that those players who did not sit out].
You may be wondering why you seem to be getting good scores throughout the session but your final score seems much less. This can be because if you start with a reasonable result, but the board has only been played a few times, the Tablet may show you have got 100% when you play it because you have the best score so far, but most later results are better than yours and so by the end your 100% is only say 40% on the board.
The more times a board is played the more representative the score is of your performance. If a board is only played 4 times then you (NS) may get a perfectly sensible result but if the other 3 EWs have had a disaster then you might find that you have ‘bottom’ through no fault of your own i.e. every other NS has a better score than you do! It could be as simple as that they all gave away an extra overtrick!
So what is the answer to the question – why does my score change so much at the end? You may need an example to understand this. Let’s assume a simple movement with 9 tables and we play 9 rounds of 3 boards with 2 winners (27 boards). Every NS plays every EW and everyone plays every board. [This produces an absolutely fair result – if you do not play every pair or every board it introduces small variations that may slightly distort the measure of your real performance].
At the end of the penultimate round every board has been played 8 times and so the maximum score on each board at that stage is 14 points. So the maximum any pair could have scored is 24 x 14 = 336. Your score so far is worked out as percentage of 336 and if you got a total of 200 points at that stage it would show that you had 59.5%.
On the last round of 3 boards the most you could get would be 3 x 16 (the new ‘top’) = 48. BUT all the boards that you have already played will also be played again by other pairs and so you will get 2, 1 or 0 extra on each of the 24 boards that you have already played. At the very extremes it would be theoretically possible for you to get an extra 48 points from the boards you have already played – or 0 if you were very unlucky. If you got 3 outright tops on the last 3 boards (total 48) and 48 from the earlier boards, your score could go up the 200 +48 + 48 = 296.
The total maximum score is 27 x 16 = 432 and therefore your final percentage could go up to 68.5% (296/432). Conversely, if you got 3 bottoms on the last 3 boards and 0 from the earlier 24 boards, then you percentage score could go down - to 200/432 = 46.2%. In practice of course you are very unlikely to have such an extreme result but this example does show that your score could theoretically go up or down by around 10% on the last round! It is not uncommon to gain or lose 5% on the last round.
The way events are scored is one of the factors that influence directors when they are choosing movements. The aim is to get each board played as many times as possible and for pairs to play as many pairs as possible. As we always try to play 24 boards, some movements work better than others for different table numbers. Other factors, such as wanting only one winner (in competitions), having enough stationary pairs to allow those to sit who need to, avoiding sharing and avoiding too many complicated moves when it is crowded, all make selecting the movement a critical and stressful activity, especially when members come late and the Table Numbers change!
Just remember that your score is not just a measure of how well you played – it is as much a measure of how badly the players did who played the same hands! It is possible to do well playing badly, or do badly playing well. In the long term your scores reflect your performance and if you are improving you should see it in the trend of your results but don’t expect to consistently improve – there is a large element of luck in bridge!