Summarized below are the 4 IMP scoring methods supported by ACBLscore:
IMPs using computed datum:
A datum is calculated by averaging all the results on a board after removing some high and low results. The datum is rounded to the nearest 10 points. If the last digit of the computed datum is 5, it is rounded to the nearest even score. For example, 425 is rounded to 420 and 435 is rounded to 440. Each result is IMPed with the datum. The default number of scores removed is 5% high and 5% low scores.
ADJUSTED BOARDS: AVE 0 IMPs, AVE+ 3 IMPs
FOULED BOARDS: A separate datum is calculated for each group.
Total IMPs:
Each result is IMPed with every other result on a board. The sum of the IMP comparisons is the score.
ADJUSTED BOARDS: AVE 0 IMPs, AVE+ 3 IMPs x (number of results - 1)
FOULED BOARDS: Each group is IMPed separately, then factored by (number of results - 1)/(size of group - 1)
Average IMPs:
Each result is IMPed with every other result on a board. The sum of the IMP comparisons is then divided by the number of comparisons.
ADJUSTED BOARDS: AVE 0 IMPs, AVE+ 3 IMPs
FOULED BOARDS: Each group is IMPed separately.
IMPs using a predetermined datum:
Each result is IMPed with the predetermined datum. The datum is entered by using the PDAT command.
ADJUSTED BOARDS: AVE 0 IMPs, AVE+ 3 IMPs
FOULED BOARDS: A separate datum is calculated for each group using the method described in IMPs using computed datum.