The pairs scoring methods available are:
Each score on a board is treated as separate entity and is ranked with all other scores as to its relative performance. Each pair is assigned a matchpoint score of 2 for every other pair they outscore and 1 for every other pair with whom they tie. They receive zero for every other pair by whom they are out scored. There are variations on the way these scores are represented, but in principle the scores are an accumulation of wins, draws and losses. The size of the difference in the original board scores are not considered, just that they are different.
All forms of Butler scoring rely on a datum score with which all the scores for a board are compared. The difference between the score a pair achieved and the datum score is then converted to an IMP score.
With average Butler the datum is determined by taking an average of all the scores on the board after eliminating an arbitrary number of the highest and lowest scores.
With halfway Butler the datum is determined by taking the middle (median) of all the scores on the board. Where there are an even number of scores on the board you will be asked whether you wish to use the score counting halfway from the top or bottom.(e.g. with 10 scores the top uses the 5th score, the bottom the 6th score).
With Leaders Butler the datum is determined by taking an average of all the scores from the leading tables in the session. This form of scoring only applies to a Swiss pairs event and a barometer scored event, scored round by round.
You are asked to supply the number of leading results to use in the determining the average for the board after eliminating either one or two of the highest and lowest scores from that group.
The leaders are sitting at the top tables in the event. Table 1 has the two winning pairs, table 2 the next two pairs etc.
With field Butler the scores achieved at each table are compared with all other tables in the event. Each pair is teamed up with every other pair sitting in the opposite seat at all other tables, and the result converted to IMPs. The total IMPs is the result on the board for that pair.
This scoring method only applies to events where the Epson percentage score has been entered as the scores achieved on the boards.
The scores are entered as a percentage of the top available on the board. Those scores are then converted to matchpoints based on the top for the board. Scores are then accumulated based on those awarded scores.
Normal matchpoint scores are produced, and the scores expressed as a percentage are then used to produce an IMP score. The IMP score is produced by subtracting 50 from the percentage achieved on each board. Therefore a 54% score by NS is 4 IMPs to NS and -4 IMPs to EW. The IMPs are summed over all boards to produce the overall session score. These total scores can be converted to VPs as a last step in producing the event outright scores.
The sum of the original scores achieved by each pair are summed to produce the total for the session. These scores are accumulated to produce the event outright scores.
This is not a true scoring method. The sum of the scores achieved by each pair are summed to produce the total for the session. These scores are not accumulated to produce the event outright scores. This is used to produce a check total of the scores achieved by each pair and are published as a session score for pairs to check the data entry.