The current SALT teams competition is being scored using VPs or Victory Points. Probably none of us in the staircase division knew what these were so I asked Robin Devries and this article is an amplification of his explanation - thanks Robin!
VPs are a teams scoring system developed by the World Bridge Federation to ensure that each IMP scored by a team was important but not necessarily of equal value. It is a sliding scale so that a small difference in IMPs between the two teams is worth more VPs than the extra VPs scored from a large IMP difference. In other words, diminishing returns set in.
Interestingly, the IMPs scale itself is similarly a sliding scale, based on the difference in matchpoints, so VPs are a sliding scale on a sliding scale!
The way it works is that 20 VPs are awarded to each teams match and the allocation of them between the two teams depends on the difference between the IMPs earned by each team. NB the conversion scale used depends on the number of boards per match.
For example:
If Team A and Team B each score 25 IMPS (difference = 0) then each team shares the 20 VPs equally ie 10 VPs each.
Difference = 2 IMPs winner VPs = 10.6
Difference = 5 IMPs winner VPs = 11.3
Difference = 10 IMPs winner VPs = 12.5
Near the extreme, if Team A scores 70 Imps and Team B 5 IMPs (difference = 65), then Team A would be awarded 19.86 VPs and poor old Team B gets the dregs: 0.14 VPs.
To quote the WBF "For example, in a 16-board match, the winners would get 15 VPs for a 20 IMP margin, but would need an additional 40 IMPs to get the full 20 VPs."
The graph above shows how the split between teams determines the distribution of the VP’s.
Using the match between Team Wayland and Team Kingsford-Smith in Round 1 as an example:
Team Wayland won by 8 IMPS. You can see on the chart that that equates to 12.1 VPs to the winners and 7.9 VPs to the losing team.
If you are interested, go to the WBF website where you can download the conversion table and read a very informative article explaining the rationale behind the scales.
