[Buddyboy1]

For a long time I have noticed that IMP scoring shown for some hands has inconsistencies. For example, one pair plays a board in a major game making four for 620. Another plays the same board in No Trump making four and scoring 630. In spite of one pair scoring more than the other I see them awarded equal points. Is that a glitch or is it deliberate.

Today I played a board, bid and making 4♥ for 620. Another pair made the same bid with the same result for the same 620. One pair was awarded +9.3, the other pair was awarded +8.4. Again, was this a glitch or was it deliberate?

Here is the described example.

[sfi]

The first one simply reflects the IMP scoring table, where a difference of 10 points translates to a 0 IMP difference. Details are here.

The second one is likely a function of timing - the score for their table may not have been recalculated to include a recent result while the hand is being played at other tables. Eventually it sorts itself out. This time it was in your favour, and you (and the other two pairs who made 4H) finished with +10.47 on the hand.

[Buddyboy1]

sfi, on 2021-May-08, 16:24, said:

The first one simply reflects the IMP scoring table, where a difference of 10 points translates to a 0 IMP difference. Details are here.

The second one is likely a function of timing - the score for their table may not have been recalculated to include a recent result while the hand is being played at other tables. Eventually it sorts itself out. This time it was in your favour, and you (and the other two pairs who made 4H) finished with +10.47 on the hand.

Thank you. I can see scores changing as results are accumulated but, to me, identical scores should reflect identical BBO scores at any point in time. Nonetheless, I am reassured that there is nothing amiss.

[sfi]

Buddyboy1, on 2021-May-08, 18:09, said:

Thank you. I can see scores changing as results are accumulated but, to me, identical scores should reflect identical BBO scores at any point in time.

I quite agree, but it might actually be quite a big change to make sure everything is consistent every time you look at it. For me it just goes on the list of quirks to be occasionally reminded about.

[Douglas43]

IMP scoring is really designed for head-to-head matches between teams of 4 (or teams of 8) and has been since it supplanted total score in the 50's and 60's. It is good for that.

[paulg]

Buddyboy1, on 2021-May-08, 18:09, said:

Thank you. I can see scores changing as results are accumulated but, to me, identical scores should reflect identical BBO scores at any point in time. Nonetheless, I am reassured that there is nothing amiss.

When BBO was first introduced, it was the case that all result updates were reflected immediately to everyone who was online and identical table scores would result in identical BBO scores. In IT terms, everything was synchronised.

This works well with a small number of users, a small number of tables and not too many results. It is one reason that people liked the BBO Windows client.

However it does not scale well and BBO addressed this problem (well before lockdown started) by moving to a more asynchronous model with the newer clients they introduced. In essence, instead of sending every result to everyone as soon as it happens, they now bundle up the results and send more of them less frequently. This is more efficient in terms of reducing server load and network load, which means that BBO can support more clients, tables and boards without slowing down (as much).

The consequence of this model is that every user receives a new bundle of results at different times, which results in transient differences.

It is probable that different design decisions in the early days of BBO could have addressed this problem, but unlike many I think they've done a reasonable job in the circumstances.

(At least this is how I think it all works. I don't work for BBO but this is what I've assumed given discussions over the years)

[Joe_Old]

Another way to get up to date results is to use the blue "refresh" button.