[Antrax]

You can use Google Docs, they have a decent spreadsheet.

[ArtK78]

It astonishes me that players continue to think that computer generated hands are biased against a player. Quite frankly, even if a bias existed, everyone still plays the same hands.

If there really is a bias in favor of finesses not working, one should incorporate this into one's overall strategy of play. Let me know if you suddenly become a master of the robot games by playing for all finesses to fail.

When I was a new player (back in the 70's) people complained all the time about computer hands. I rarely hear that anymore. But every so often someone complains about a bad break by breaking out the old "darn computer hands" complaint.

[tx10s]

Bbradley62, on 2015-January-20, 21:55, said:

Since I was puzzled as to how your statistics are so different that the ones I recently posted, I looked at the 11 tournaments that you played 1/14-1/19. Being a little lazy, I only kept track of which finesses worked/didn't for you when you declared (105 of the 132 hands). I also only kept track of missing Aces, Kings and Queens, so that my spreadsheet would be a little easier to follow if you want to look at it (although I don't see how to post it). There were certainly many opportunities to finesse for missing Jacks and Tens, but I did not tabulate those.

On those 105 hands, you had 49 opportunities to finesse for a missing Ace (when you had the K but not the Q of the suit in question). 28 of the 49 Aces were onside.

On those 105 hands, you had 51 opportunities to finesse for a missing King. Sometimes you held AQJ of the suit between the two hands (in which case "onside" meant in front of the Ace) and sometimes you held A in one and Q in the other without the J (in which case "onside" meant in front of the Q. 31 of the 51 missing Kings were onside.

On those 105 hands, you had one-way finesses for missing Queens 36 times, and the missing Queen was onside 13 times.

So, on those 105 hands you had 136 opportunities to finesse for missing A/K/Q (not that you took all those finesses, or even that it was a good idea to do so) and the missing honor was onside 72 times (53%).

I looked at the same hands, and my count was similar, 73 out of 134, actually slightly more optimistic than your count. I then included all of the tournaments since I made my posting, and the finesses for the players were 53% successful, the highest I have ever seen for that many tournaments in all of my reviews. I think we can agree that there is no significant difference in how we evaluate finesses. Below is a copy of the spreadsheet of the 20 tournaments I evaluated before I posted. (It is interesting that I had the highest success rate after posting my comment, but I will leave conspiracy theory to others.) If you have time to check the previous 20, I would like to know what numbers you came up with.

Finesses
Player Robots Total
Date Tourn Win Lose Win Lose Win Lose
31-Dec 5357 4 6 1 4 7
1-Jan 9466 5 6 2 3 8 8
1-Jan 9705 6 7 1 7 7
1-Jan 864 2 3 2 3
2-Jan 7203 4 6 1 5 6
3-Jan 3698 3 9 3 1 4 12
4-Jan 9091 7 10 1 2 9 11
4-Jan 92 6 5 4 3 9 9
5-Jan 5308 4 5 7 1 5 12
5-Jan 6810 4 12 1 1 5 13
6-Jan 1798 4 1 1 5 1
6-Jan 3864 3 7 1 3 8
6-Jan 4027 7 1 1 7 2
8-Jan 3839 7 12 7 12
8-Jan 4589 3 11 2 2 5 13
10-Jan 1077 2 7 2 2 9
11-Jan 5532 3 9 2 1 4 11
11-Jan 6086 4 3 1 4 4
12-Jan 1855 4 5 5 1 5 10
12-Jan 2753 3 7 4 2 5 11
Totals 85 132 37 20 105 169

Pct 39.2% 64.9% 38.3%

[tx10s]

tx10s, on 2015-January-21, 13:42, said:

I looked at the same hands, and my count was similar, 73 out of 134, actually slightly more optimistic than your count. I then included all of the tournaments since I made my posting, and the finesses for the players were 53% successful, the highest I have ever seen for that many tournaments in all of my reviews. I think we can agree that there is no significant difference in how we evaluate finesses. Below is a copy of the spreadsheet of the 20 tournaments I evaluated before I posted. (It is interesting that I had the highest success rate after posting my comment, but I will leave conspiracy theory to others.) If you have time to check the previous 20, I would like to know what numbers you came up with.

Finesses
Player Robots Total
Date Tourn Win Lose Win Lose Win Lose
31-Dec 5357 4 6 1 4 7
1-Jan 9466 5 6 2 3 8 8
1-Jan 9705 6 7 1 7 7
1-Jan 864 2 3 2 3
2-Jan 7203 4 6 1 5 6
3-Jan 3698 3 9 3 1 4 12
4-Jan 9091 7 10 1 2 9 11
4-Jan 92 6 5 4 3 9 9
5-Jan 5308 4 5 7 1 5 12
5-Jan 6810 4 12 1 1 5 13
6-Jan 1798 4 1 1 5 1
6-Jan 3864 3 7 1 3 8
6-Jan 4027 7 1 1 7 2
8-Jan 3839 7 12 7 12
8-Jan 4589 3 11 2 2 5 13
10-Jan 1077 2 7 2 2 9
11-Jan 5532 3 9 2 1 4 11
11-Jan 6086 4 3 1 4 4
12-Jan 1855 4 5 5 1 5 10
12-Jan 2753 3 7 4 2 5 11
Totals 85 132 37 20 105 169

Pct 39.2% 64.9% 38.3%

When I posted this, the data columns lined up nicely. When I went back to add a comment, I see that the data does not present well. In each row, the first item is the date, the second is the tournament number. The third is finesses onside for the players, the fourth is finesses offside for the player, the fifth is finesses onside for the robots, the sixth is finesses offside for the robot, the seventh is the sum of finesses onside for the players and offside for the robots (in other words the finesses that favor the player) and the eights data point is the sum of finesses offside for the player and onside for the robots.

[tx10s]

ArtK78, on 2015-January-21, 07:13, said:

It astonishes me that players continue to think that computer generated hands are biased against a player. Quite frankly, even if a bias existed, everyone still plays the same hands.

If there really is a bias in favor of finesses not working, one should incorporate this into one's overall strategy of play. Let me know if you suddenly become a master of the robot games by playing for all finesses to fail.

When I was a new player (back in the 70's) people complained all the time about computer hands. I rarely hear that anymore. But every so often someone complains about a bad break by breaking out the old "darn computer hands" complaint.

That was great sarcasm, but ignores the data. Obviously, if all finesses were offside, the game would be easier. Obviously, everyone plays the same hand, but I'm sure the experts (not me) would know how to adjust their strategy for the bias built into a dealing program. I have already seen that at BBO by all the people who bid the frequent "cheap" slams that the robot program puts out. When I say cheap slams, the average slam hand that I have looked at (about 30) has an average of 29 HCP and barely over 30 total points. Additionally, I have looked for hands with over 30 points that do not make slam, and they are very few and far between.

[tx10s]

tx10s, on 2015-January-21, 13:56, said:

When I posted this, the data columns lined up nicely. When I went back to add a comment, I see that the data does not present well. In each row, the first item is the date, the second is the tournament number. The third is finesses onside for the players, the fourth is finesses offside for the player, the fifth is finesses onside for the robots, the sixth is finesses offside for the robot, the seventh is the sum of finesses onside for the players and offside for the robots (in other words the finesses that favor the player) and the eights data point is the sum of finesses offside for the player and onside for the robots.

Sorry, I had blanks instead of zeros, here is the same data again with the zeros, although still not well presented. I have tried several methods without success, so I will see if I can get Google spreadsheets to work.

                Finesses                                        
                Player          Robots          Total   
Date    Tourn   Win     Lose    Win     Lose    Win     Lose
31-Dec  5357    4       6       1       0       4       7
1-Jan   9466    5       6       2       3       8       8
1-Jan   9705    6       7       0       1       7       7
1-Jan   864     2       3       0       0       2       3
2-Jan   7203    4       6       0       1       5       6
3-Jan   3698    3       9       3       1       4       12
4-Jan   9091    7       10      1       2       9       11
4-Jan   92      6       5       4       3       9       9
5-Jan   5308    4       5       7       1       5       12
5-Jan   6810    4       12      1       1       5       13
6-Jan   1798    4       1       0       1       5       1
6-Jan   3864    3       7       1       0       3       8
6-Jan   4027    7       1       1       0       7       2
8-Jan   3839    7       12      0       0       7       12
8-Jan   4589    3       11      2       2       5       13
10-Jan  1077    2       7       2       0       2       9
11-Jan  5532    3       9       2       1       4       11
11-Jan  6086    4       3       1       0       4       4
12-Jan  1855    4       5       5       1       5       10
12-Jan  2753    3       7       4       2       5       11
                                                        
        Totals  85      132     37      20      105     169

Please remember that totals are Wins: Player wins plus robot losses and Losses: Player losses plus robot wins

[barmar]

Use the "Code" style to post formatted tables. It's in the Other Styles menu.

[tx10s]

Bbradley62, on 2015-January-20, 22:01, said:

Since I don't see how to post the spreadsheet, and my dataset isn't all that big, I'll copy and paste it here, although I'd still appreciate it if someone explained how to post a file. Well, I can't get it to format nice, and I can't find the recent post about how to make nice columns, so I'll try again tomorrow...

When I see how to make nice columns, I will try to post more of my data. I am surprised that this forum has no obvious way to post a spreadsheet, or down load any file for that matter. I am hoping there is a way, and one of you experts can tell me.

[tx10s]

tx10s, on 2015-January-21, 14:51, said:

Sorry, I had blanks instead of zeros, here is the same data again with the zeros, although still not well presented. I have tried several methods without success, so I will see if I can get Google spreadsheets to work.

                Finesses                                        
                Player          Robots          Total   
Date    Tourn   Win     Lose    Win     Lose    Win     Lose
31-Dec  5357    4       6       1       0       4       7
1-Jan   9466    5       6       2       3       8       8
1-Jan   9705    6       7       0       1       7       7
1-Jan   864     2       3       0       0       2       3
2-Jan   7203    4       6       0       1       5       6
3-Jan   3698    3       9       3       1       4       12
4-Jan   9091    7       10      1       2       9       11
4-Jan   92      6       5       4       3       9       9
5-Jan   5308    4       5       7       1       5       12
5-Jan   6810    4       12      1       1       5       13
6-Jan   1798    4       1       0       1       5       1
6-Jan   3864    3       7       1       0       3       8
6-Jan   4027    7       1       1       0       7       2
8-Jan   3839    7       12      0       0       7       12
8-Jan   4589    3       11      2       2       5       13
10-Jan  1077    2       7       2       0       2       9
11-Jan  5532    3       9       2       1       4       11
11-Jan  6086    4       3       1       0       4       4
12-Jan  1855    4       5       5       1       5       10
12-Jan  2753    3       7       4       2       5       11
                                                        
        Totals  85      132     37      20      105     169

Please remember that totals are Wins: Player wins plus robot losses and Losses: Player losses plus robot wins

Thank you to whoever fixed my post

[helene_t]

barmar, on 2015-January-20, 10:00, said:

If there's a tie for the best hand among the other seats, we pick one of them at random.

I don't see how this could result in a finesse bias, though.

If you were more likely to swap with East than with West when EW are tied for best hand, it would produce losing finesses for declarer.

[barmar]

In the "Robot finesse" column, are these cases where the robot took a finesse and it won or lost, or are they cases where the robot COULD have taken a finesse, and it would have won or lost.

With AQxx opposite a singleton, and sufficient transportation and ruffing power, the robots often try to ruff out the K rather than just take the finesse, especially if the bidding indicates strength in the hand behind the AQ. So it probably takes fewer finesses than you do, and takes them in cases where they're more likely to succeed.

Basically, I think what you're seeing is that the robots are better at calculating the odds and using them to guide their play. This is the kind of thing computers are good at.

[tx10s]

barmar, on 2015-January-21, 14:57, said:

Use the "Code" style to post formatted tables. It's in the Other Styles menu.

                Finesses                                        
                Player          Robots          Total   
Date    Tourn   Win     Lose    Win     Lose    Win     Lose
29-Oct  254     5       8       0       0       5       8
28-Oct  4033    1       6       1       2       3       7
28-Oct  2207    7       10      0       0       7       10
27-Oct  7233    4       8       1       0       4       9
26-Oct  9970    7       2       2       1       8       4
25-Oct  5406    8       8       1       2       10      9
24-Oct  9445    3       9       2       1       4       11
24-Oct  8268    2       9       0       0       2       9
23-Oct  2680    7       5       1       1       8       6
23-Oct  2038    1       3       0       0       1       3
22-Oct  7000    4       4       1       0       4       5
22-Oct  5668    2       5       2       3       5       7
21-Oct  718     6       5       2               6       7
21-Oct  524     4       9       2       4       8       11
20-Oct  3821    4       11      0       0       4       11
19-Oct  9454    5       6       0       0       5       6
19-Oct  7468    4       4       1       1       5       5
18-Oct  2709            6       0       1       1       6
18-Oct  1277    5       7       2       2       7       9
17-Oct  7281    4       6       0       0       4       6
                                                        
        Totals  83      131     18      18      101     149

Thanks for the tip, it works well.  Attached is another set of data in my finesses evaluation, dates are 2014

[tx10s]

[quote name='tx10s' timestamp='1421874455' post='830909']

                Finesses                                        
                Player          Robots          Total   
Date    Tourn   Win     Lose    Win     Lose    Win     Lose
29-Oct  254     5       8       0       0       5       8
28-Oct  4033    1       6       1       2       3       7
28-Oct  2207    7       10      0       0       7       10
27-Oct  7233    4       8       1       0       4       9
26-Oct  9970    7       2       2       1       8       4
25-Oct  5406    8       8       1       2       10      9
24-Oct  9445    3       9       2       1       4       11
24-Oct  8268    2       9       0       0       2       9
23-Oct  2680    7       5       1       1       8       6
23-Oct  2038    1       3       0       0       1       3
22-Oct  7000    4       4       1       0       4       5
22-Oct  5668    2       5       2       3       5       7
21-Oct  718     6       5       2               6       7
21-Oct  524     4       9       2       4       8       11
20-Oct  3821    4       11      0       0       4       11
19-Oct  9454    5       6       0       0       5       6
19-Oct  7468    4       4       1       1       5       5
18-Oct  2709            6       0       1       1       6
18-Oct  1277    5       7       2       2       7       9
17-Oct  7281    4       6       0       0       4       6
                                                        
        Totals  83      131     18      18      101     149

Thanks for the tip, it works well.  Attached is another set of data in my finesses evaluation, dates are 2014

Here is another set, please excuse my using a reply to post the data, but for some reason, the Code style will not copy a full spreadsheet in the Fast Replay section:

        Finesses                                        
        Player          Robots          Total   
Tourn   Win     Lose    Win     Lose    Win     Lose
7100    7       5       1       0       7       6
1024    6       6       1       3       9       7
9941    3       9       2       0       3       11
1065    4       4       4       3       7       8
8485    6       10      0       0       6       10
8890    5       4       2       1       6       6
5981    4       5       3       1       5       8
56      3       7       3       1       4       10
564     7       5       2       0       7       7
2156    3       6       2       0       3       8
6396    4       5       2       0       4       7
6703    5       7       0       0       5       7
8371    2       7       1       0       2       8
8482    4       6       0       0       4       6
1936    2       4       2       3       5       6
2075    3       8       0       1       4       8
3540    4       9       1       1       5       10
6698    6       9       1       2       8       10
2715    3       8       0       0       3       8
2936    8       7       2       2       10      9
                                                
Totals  89      131     29      18      107     160

[barmar]

Try clicking on Use Full Editor.

[tx10s]

barmar, on 2015-January-21, 15:05, said:

In the "Robot finesse" column, are these cases where the robot took a finesse and it won or lost, or are they cases where the robot COULD have taken a finesse, and it would have won or lost.

With AQxx opposite a singleton, and sufficient transportation and ruffing power, the robots often try to ruff out the K rather than just take the finesse, especially if the bidding indicates strength in the hand behind the AQ. So it probably takes fewer finesses than you do, and takes them in cases where they're more likely to succeed.

Basically, I think what you're seeing is that the robots are better at calculating the odds and using them to guide their play. This is the kind of thing computers are good at.

An interesting point, but my finesse calculations were only based on potential finesses, I did not record which finesses were actually taken, as my analysis was done after the hands were played by just looking at the card distribution.

[1eyedjack]

I am missing something but I don't understand why (excluding total columns) there are 4 columns when I would expect 2.

Every finesse that is working for one side is losing for the other. Say you (human) are South, North has AQ and East has K. This is a working finesse for the robot, failing for human.

So I would expect this to count +1 in both the "player lose" and "robot win" columns. And I would expect this double entry to balance for each example, so that the total for the player lose column should never depart from the same total for the robot win column. But in your spreadsheet these totals do differ. What's that all about?

[barmar]

helene_t, on 2015-January-21, 15:03, said:

If you were more likely to swap with East than with West when EW are tied for best hand, it would produce losing finesses for declarer.

There's a very tiny bias. We use rand()%3 to choose a seat to swap with (0 = W, 1 = N, 2 = E), and rand() returns a number from 0 to 2^31-1. There's one more value whose modulus is 0 than 1 or 2, so there's a 0.00000014% bias towards West. But this has to be multiplied by the probability that EW are tied for best hand in the first place; this can't be any more than 1 in 16, so we're talking about only 0.000000008%.

For this to become noticeable you'd have to examine billions of hands, not the few hundred that tx10 and bbradley62 looked at.

[barmar]

barmar, on 2015-January-22, 15:30, said:

For this to become noticeable you'd have to examine billions of hands, not the few hundred that tx10 and bbradley62 looked at.

BTW, we currently generate 10-15 million hands a year. So the total number of hands produced in the entire history of BBO is probably around 100 million. Nowhere close to making that bias noticeable even if we examined every hand (we can't actually do that -- I think our hand archives only go back to around 2007).

[Bbradley62]

1eyedjack, on 2015-January-22, 13:50, said:

Every finesse that is working for one side is losing for the other. Say you (human) are South, North has AQ and East has K. This is a working finesse for the robot, failing for human.

I don't know OP's methodology, but I over-simplified by only looking at it from the point of view of declarer. Suppose:

---

If NS declares, the spade finesse (hoping to find K in front of the Q) is successful. If EW declares, the spade finesse (hoping to find A in front of the K) is also successful.

[hrothgar]

tx10s, on 2015-January-19, 16:23, said:

If you read the post, the sampling was done on hands that were already dealt. The fact that the finesse split ranged between 38.9% and 41% for sets of twenty tournaments averaging 281 finesses/ open endings with an overall average of 40.0% I felt was significant enough

Here's the rub...

People are very good at finding patterns in data. If you spend long enough staring at a random set of hands, odds are your going to find something weird about it.

On this set of hands, you're upset because the finesses don't work
On that set of hands, you're annoyed because E/W gets more HCPs than North South
On some other set of hands, the clubs never break well

It is for this reason that you start by specifying a hypothesis, and then test your hypothesis using a completely different data set.

This notion is fundamental to any kind of serious analysis...