Study 8J45 Main

Actual Play vs. Double-Dummy

by Richard Pavlicek

How does actual play compare with double-dummy play? The question has often been asked, but concrete answers are rare because “actual play” is difficult to define. Clearly it implies imperfection to some degree, but exactly how much is unclear. Whatever the case, if both sides are equally imperfect, the errors should tend to cancel out in the long run, approaching the double-dummy state.

This study compares actual play from four major annual team events — Vanderbilt, Spingold, U.S. Championship and World Championship — with double-dummy play. The database from vugraph archives 1996-2014 consists of 80,138 results from 72 events, however 196 passouts are removed to leave 79,942 contracts. The playing field of “expert vs. expert” should provide a viable comparison, though the henchmen around here would prefer “Spy vs. Spy” from Mad Magazine.

General Case After the Opening Lead Conclusion

General Case

The first table shows various contract groups and the number of times each occurred. The remaining columns show the number of times made, percent made and average tricks won, both in actual play and at double-dummy. Corresponding values are placed side-by-side for comparison. The second table does the same for the 35 specific contracts. Rows tinted gold show contracts in which double-dummy play surpassed actual play in both percent made and average tricks won.

The overall picture is that actual declarer play does slightly better than double-dummy play except at the slam level where double-dummy play has a slight edge. The reason is apparent: The opening lead gives the defense a considerable advantage at double-dummy; e.g., the perfect lead will sometimes bury a contract before declarer has a chance. As the contract level increases, the opening lead tends to be less crucial, so the advantage tapers off, disappearing entirely from 5 NT upward. The narrow exception with 4 in the second table is probably a fluke that would reverse in a larger sample.

Contracts by Group
Group Times Made DD Make % DD Trick Avg DD
All contracts 79942 51448 49585 64.36 62.03 9.28 9.21
Notrump 22689 15621 14517 68.85 63.98 8.72 8.56
Suit 57253 35827 35068 62.58 61.25 9.50 9.47
Major suit 42130 27316 26780 64.84 63.57 9.50 9.47
Hearts 19401 12602 12477 64.96 64.31 9.58 9.57
Spades 22729 14714 14303 64.74 62.93 9.43 9.39
Minor suit 15123 8511 8288 56.28 54.80 9.50 9.47
Clubs 7168 3912 3843 54.58 53.61 9.53 9.51
Diamonds 7955 4599 4445 57.81 55.88 9.47 9.43
Partscore 29500 18144 17062 61.51 57.84 8.08 7.96
Game not slam 44495 29359 28461 65.98 63.96 9.75 9.71
Slam (6 or 7) 5947 3945 4062 66.34 68.30 11.71 11.77
1 level 5786 3925 3546 67.84 61.29 7.11 6.84
2 level 11771 7715 7356 65.54 62.49 7.95 7.84
3 level 25844 16528 15558 63.95 60.20 8.94 8.85
4 level 24312 16202 16030 66.64 65.93 9.93 9.93
5 level 6282 3133 3033 49.87 48.28 10.31 10.27
6 level 5152 3434 3503 66.65 67.99 11.63 11.68
7 level 795 511 559 64.28 70.31 12.26 12.37
1 of suit 851 583 560 68.51 65.80 7.25 7.10
2 of suit 10314 6889 6624 66.79 64.22 8.00 7.91
3 of suit 10459 5783 5472 55.29 52.32 8.58 8.52
4 of suit 23976 15919 15757 66.40 65.72 9.92 9.92
5 of suit 6265 3123 3022 49.85 48.24 10.31 10.27
6 of suit 4690 3095 3153 65.99 67.23 11.61 11.66
7 of suit 698 435 480 62.32 68.77 12.20 12.32

Contracts by Group
Group	Times	Made	DD	Make %	DD	Trick Avg	DD
All contracts	79942	51448	49585	64.36	62.03	9.28	9.21
Notrump	22689	15621	14517	68.85	63.98	8.72	8.56
Suit	57253	35827	35068	62.58	61.25	9.50	9.47
Major suit	42130	27316	26780	64.84	63.57	9.50	9.47
Hearts	19401	12602	12477	64.96	64.31	9.58	9.57
Spades	22729	14714	14303	64.74	62.93	9.43	9.39
Minor suit	15123	8511	8288	56.28	54.80	9.50	9.47
Clubs	7168	3912	3843	54.58	53.61	9.53	9.51
Diamonds	7955	4599	4445	57.81	55.88	9.47	9.43
Partscore	29500	18144	17062	61.51	57.84	8.08	7.96
Game not slam	44495	29359	28461	65.98	63.96	9.75	9.71
Slam (6 or 7)	5947	3945	4062	66.34	68.30	11.71	11.77
1 level	5786	3925	3546	67.84	61.29	7.11	6.84
2 level	11771	7715	7356	65.54	62.49	7.95	7.84
3 level	25844	16528	15558	63.95	60.20	8.94	8.85
4 level	24312	16202	16030	66.64	65.93	9.93	9.93
5 level	6282	3133	3033	49.87	48.28	10.31	10.27
6 level	5152	3434	3503	66.65	67.99	11.63	11.68
7 level	795	511	559	64.28	70.31	12.26	12.37
1 of suit	851	583	560	68.51	65.80	7.25	7.10
2 of suit	10314	6889	6624	66.79	64.22	8.00	7.91
3 of suit	10459	5783	5472	55.29	52.32	8.58	8.52
4 of suit	23976	15919	15757	66.40	65.72	9.92	9.92
5 of suit	6265	3123	3022	49.85	48.24	10.31	10.27
6 of suit	4690	3095	3153	65.99	67.23	11.61	11.66
7 of suit	698	435	480	62.32	68.77	12.20	12.32

Specific Contracts
Contract Times Made DD Make % DD Trick Avg DD
1 45 25 28 55.56 62.22 6.53 6.53
1 72 39 31 54.17 43.06 6.74 6.38
1 230 153 153 66.52 66.52 7.29 7.23
1 504 366 348 72.62 69.05 7.38 7.20
1 NT 4935 3342 2986 67.72 60.51 7.09 6.79
2 847 505 484 59.62 57.14 7.84 7.72
2 1385 914 860 65.99 62.09 8.01 7.91
2 3297 2233 2187 67.73 66.33 8.06 7.98
2 4785 3237 3093 67.65 64.64 7.99 7.89
2 NT 1457 826 732 56.69 50.24 7.59 7.39
3 2303 1315 1271 57.10 55.19 8.62 8.59
3 2563 1527 1473 59.58 57.47 8.71 8.66
3 2704 1437 1329 53.14 49.15 8.49 8.42
3 2889 1504 1399 52.06 48.43 8.51 8.41
3 NT 15385 10745 10086 69.84 65.56 9.19 9.07
4 782 374 360 47.83 46.04 9.36 9.25
4 702 347 328 49.43 46.72 9.32 9.26
4 10406 7154 7204 68.75 69.23 10.00 10.03
4 12086 8044 7865 66.56 65.08 9.92 9.91
4 NT 336 283 273 84.23 81.25 10.68 10.57
5 2110 1050 1027 49.76 48.67 10.28 10.26
5 2124 1059 1023 49.86 48.16 10.32 10.30
5 1183 529 490 44.72 41.42 10.19 10.08
5 848 485 482 57.19 56.84 10.55 10.50
5 NT 17 10 11 58.82 64.71 10.59 10.76
6 956 582 595 60.88 62.24 11.56 11.62
6 944 621 627 65.78 66.42 11.65 11.71
6 1371 945 958 68.93 69.88 11.66 11.70
6 1419 947 973 66.74 68.57 11.56 11.63
6 NT 462 339 350 73.38 75.76 11.79 11.87
7 125 61 78 48.80 62.40 11.91 12.14
7 165 92 103 55.76 62.42 11.93 12.04
7 210 151 156 71.90 74.29 12.40 12.45
7 198 131 143 66.16 72.22 12.40 12.53
7 NT 97 76 79 78.35 81.44 12.65 12.69

Specific Contracts
Contract	Times	Made	DD	Make %	DD	Trick Avg	DD
1	45	25	28	55.56	62.22	6.53	6.53
1	72	39	31	54.17	43.06	6.74	6.38
1	230	153	153	66.52	66.52	7.29	7.23
1	504	366	348	72.62	69.05	7.38	7.20
1 NT	4935	3342	2986	67.72	60.51	7.09	6.79
2	847	505	484	59.62	57.14	7.84	7.72
2	1385	914	860	65.99	62.09	8.01	7.91
2	3297	2233	2187	67.73	66.33	8.06	7.98
2	4785	3237	3093	67.65	64.64	7.99	7.89
2 NT	1457	826	732	56.69	50.24	7.59	7.39
3	2303	1315	1271	57.10	55.19	8.62	8.59
3	2563	1527	1473	59.58	57.47	8.71	8.66
3	2704	1437	1329	53.14	49.15	8.49	8.42
3	2889	1504	1399	52.06	48.43	8.51	8.41
3 NT	15385	10745	10086	69.84	65.56	9.19	9.07
4	782	374	360	47.83	46.04	9.36	9.25
4	702	347	328	49.43	46.72	9.32	9.26
4	10406	7154	7204	68.75	69.23	10.00	10.03
4	12086	8044	7865	66.56	65.08	9.92	9.91
4 NT	336	283	273	84.23	81.25	10.68	10.57
5	2110	1050	1027	49.76	48.67	10.28	10.26
5	2124	1059	1023	49.86	48.16	10.32	10.30
5	1183	529	490	44.72	41.42	10.19	10.08
5	848	485	482	57.19	56.84	10.55	10.50
5 NT	17	10	11	58.82	64.71	10.59	10.76
6	956	582	595	60.88	62.24	11.56	11.62
6	944	621	627	65.78	66.42	11.65	11.71
6	1371	945	958	68.93	69.88	11.66	11.70
6	1419	947	973	66.74	68.57	11.56	11.63
6 NT	462	339	350	73.38	75.76	11.79	11.87
7	125	61	78	48.80	62.40	11.91	12.14
7	165	92	103	55.76	62.42	11.93	12.04
7	210	151	156	71.90	74.29	12.40	12.45
7	198	131	143	66.16	72.22	12.40	12.53
7 NT	97	76	79	78.35	81.44	12.65	12.69

Study 8J45 Main Top Actual Play vs. Double-Dummy

After the Opening Lead

The next two tables show a comparison after the actual opening lead. That is, double-dummy play begins with the first play from dummy. (This reduced the database to 77,406 contracts, because some results did not include the play or opening lead.) Essentially, this removes the defensive advantage of the first strike, so double-dummy play surges to the front in each category — except for 1 (obviously unreliable based on little data) and 2 in percent made only, a curious mystery but probably a fluke. Another way of looking at it is that the actual declarer loses the advantage of a favorable lead; he may still get one but so will the double-dummy declarer.

Contracts by Group
Group Times Made DD Make % DD Trick Avg DD
All contracts 77406 49810 52473 64.35 67.79 9.28 9.44
Notrump 21955 15113 15769 68.84 71.82 8.72 8.92
Suit 55451 34697 36704 62.57 66.19 9.50 9.65
Major suit 40798 26447 27976 64.82 68.57 9.50 9.65
Hearts 18809 12222 13036 64.98 69.31 9.58 9.75
Spades 21989 14225 14940 64.69 67.94 9.42 9.57
Minor suit 14653 8250 8728 56.30 59.56 9.50 9.63
Clubs 6943 3795 4056 54.66 58.42 9.54 9.67
Diamonds 7710 4455 4672 57.78 60.60 9.47 9.60
Partscore 28560 17562 18116 61.49 63.43 8.08 8.17
Game not slam 43129 28449 30157 65.96 69.92 9.75 9.96
Slam (6 or 7) 5717 3799 4200 66.45 73.47 11.71 11.91
1 level 5573 3788 3832 67.97 68.76 7.12 7.15
2 level 11391 7471 7712 65.59 67.70 7.95 8.05
3 level 25091 16021 16789 63.85 66.91 8.94 9.13
4 level 23547 15697 16722 66.66 71.02 9.93 10.12
5 level 6087 3034 3218 49.84 52.87 10.31 10.44
6 level 4949 3301 3646 66.70 73.67 11.63 11.84
7 level 768 498 554 64.84 72.14 12.26 12.40
1 of suit 820 560 565 68.29 68.90 7.25 7.29
2 of suit 9996 6682 6875 66.85 68.78 8.01 8.11
3 of suit 10168 5611 5853 55.18 57.56 8.58 8.69
4 of suit 23220 15422 16441 66.42 70.81 9.92 10.11
5 of suit 6070 3024 3206 49.82 52.82 10.31 10.43
6 of suit 4504 2974 3288 66.03 73.00 11.61 11.82
7 of suit 673 424 476 63.00 70.73 12.20 12.35

Contracts by Group
Group	Times	Made	DD	Make %	DD	Trick Avg	DD
All contracts	77406	49810	52473	64.35	67.79	9.28	9.44
Notrump	21955	15113	15769	68.84	71.82	8.72	8.92
Suit	55451	34697	36704	62.57	66.19	9.50	9.65
Major suit	40798	26447	27976	64.82	68.57	9.50	9.65
Hearts	18809	12222	13036	64.98	69.31	9.58	9.75
Spades	21989	14225	14940	64.69	67.94	9.42	9.57
Minor suit	14653	8250	8728	56.30	59.56	9.50	9.63
Clubs	6943	3795	4056	54.66	58.42	9.54	9.67
Diamonds	7710	4455	4672	57.78	60.60	9.47	9.60
Partscore	28560	17562	18116	61.49	63.43	8.08	8.17
Game not slam	43129	28449	30157	65.96	69.92	9.75	9.96
Slam (6 or 7)	5717	3799	4200	66.45	73.47	11.71	11.91
1 level	5573	3788	3832	67.97	68.76	7.12	7.15
2 level	11391	7471	7712	65.59	67.70	7.95	8.05
3 level	25091	16021	16789	63.85	66.91	8.94	9.13
4 level	23547	15697	16722	66.66	71.02	9.93	10.12
5 level	6087	3034	3218	49.84	52.87	10.31	10.44
6 level	4949	3301	3646	66.70	73.67	11.63	11.84
7 level	768	498	554	64.84	72.14	12.26	12.40
1 of suit	820	560	565	68.29	68.90	7.25	7.29
2 of suit	9996	6682	6875	66.85	68.78	8.01	8.11
3 of suit	10168	5611	5853	55.18	57.56	8.58	8.69
4 of suit	23220	15422	16441	66.42	70.81	9.92	10.11
5 of suit	6070	3024	3206	49.82	52.82	10.31	10.43
6 of suit	4504	2974	3288	66.03	73.00	11.61	11.82
7 of suit	673	424	476	63.00	70.73	12.20	12.35

Specific Contracts
Contract Times Made DD Make % DD Trick Avg DD
1 42 24 28 57.14 66.67 6.60 6.83
1 70 37 34 52.86 48.57 6.71 6.51
1 219 145 148 66.21 67.58 7.27 7.37
1 489 354 355 72.39 72.60 7.37 7.41
1 NT 4753 3228 3267 67.92 68.74 7.10 7.13
2 818 493 515 60.27 62.96 7.86 7.95
2 1341 885 875 66.00 65.25 8.01 8.11
2 3188 2159 2260 67.72 70.89 8.05 8.17
2 4649 3145 3225 67.65 69.37 8.00 8.09
2 NT 1395 789 837 56.56 60.00 7.59 7.68
3 2234 1270 1336 56.85 59.80 8.62 8.75
3 2496 1492 1559 59.78 62.46 8.72 8.84
3 2633 1396 1448 53.02 54.99 8.48 8.59
3 2805 1453 1510 51.80 53.83 8.50 8.59
3 NT 14923 10410 10936 69.76 73.28 9.19 9.44
4 751 358 371 47.67 49.40 9.37 9.39
4 677 334 348 49.34 51.40 9.33 9.40
4 10100 6950 7498 68.81 74.24 10.00 10.22
4 11692 7780 8224 66.54 70.34 9.92 10.11
4 NT 327 275 281 84.10 85.93 10.66 10.87
5 2052 1023 1096 49.85 53.41 10.28 10.43
5 2054 1014 1089 49.37 53.02 10.31 10.45
5 1146 517 526 45.11 45.90 10.20 10.26
5 818 470 495 57.46 60.51 10.55 10.66
5 NT 17 10 12 58.82 70.59 10.59 11.00
6 924 567 633 61.36 68.51 11.57 11.77
6 911 602 664 66.08 72.89 11.67 11.89
6 1321 909 1001 68.81 75.78 11.66 11.85
6 1348 896 990 66.47 73.44 11.56 11.77
6 NT 445 327 358 73.48 80.45 11.79 12.04
7 122 60 77 49.18 63.11 11.91 12.16
7 161 91 103 56.52 63.98 11.94 12.09
7 202 146 155 72.28 76.73 12.39 12.48
7 188 127 141 67.55 75.00 12.41 12.56
7 NT 95 74 78 77.89 82.11 12.64 12.74

Specific Contracts
Contract	Times	Made	DD	Make %	DD	Trick Avg	DD
1	42	24	28	57.14	66.67	6.60	6.83
1	70	37	34	52.86	48.57	6.71	6.51
1	219	145	148	66.21	67.58	7.27	7.37
1	489	354	355	72.39	72.60	7.37	7.41
1 NT	4753	3228	3267	67.92	68.74	7.10	7.13
2	818	493	515	60.27	62.96	7.86	7.95
2	1341	885	875	66.00	65.25	8.01	8.11
2	3188	2159	2260	67.72	70.89	8.05	8.17
2	4649	3145	3225	67.65	69.37	8.00	8.09
2 NT	1395	789	837	56.56	60.00	7.59	7.68
3	2234	1270	1336	56.85	59.80	8.62	8.75
3	2496	1492	1559	59.78	62.46	8.72	8.84
3	2633	1396	1448	53.02	54.99	8.48	8.59
3	2805	1453	1510	51.80	53.83	8.50	8.59
3 NT	14923	10410	10936	69.76	73.28	9.19	9.44
4	751	358	371	47.67	49.40	9.37	9.39
4	677	334	348	49.34	51.40	9.33	9.40
4	10100	6950	7498	68.81	74.24	10.00	10.22
4	11692	7780	8224	66.54	70.34	9.92	10.11
4 NT	327	275	281	84.10	85.93	10.66	10.87
5	2052	1023	1096	49.85	53.41	10.28	10.43
5	2054	1014	1089	49.37	53.02	10.31	10.45
5	1146	517	526	45.11	45.90	10.20	10.26
5	818	470	495	57.46	60.51	10.55	10.66
5 NT	17	10	12	58.82	70.59	10.59	11.00
6	924	567	633	61.36	68.51	11.57	11.77
6	911	602	664	66.08	72.89	11.67	11.89
6	1321	909	1001	68.81	75.78	11.66	11.85
6	1348	896	990	66.47	73.44	11.56	11.77
6 NT	445	327	358	73.48	80.45	11.79	12.04
7	122	60	77	49.18	63.11	11.91	12.16
7	161	91	103	56.52	63.98	11.94	12.09
7	202	146	155	72.28	76.73	12.39	12.48
7	188	127	141	67.55	75.00	12.41	12.56
7 NT	95	74	78	77.89	82.11	12.64	12.74

Conclusion

The overriding impact of the tables is that actual play versus double-dummy is pretty close, so analyses based on double-dummy play should generally be on track. The henchmen of course don’t buy this, so please exit the building quietly and don’t make any fast moves.

Study 8J45 Main Top Actual Play vs. Double-Dummy