Post Mortem for the 2016 Presidential, Senate, and House Elections: December 21, 2016
I have put below a D or R for the actual outcome for each of the three elections. I added Wisconsin to the Presidential election data, which had such a high probability of the Democrats winning that it was not included in the description. Remember that all the probability data are from PredictWise and are betting-market probabilities except for the House elections, where only 25 probabilities are from betting markets---in this case all from Predictit.

For the Presidential election, the Republicans won Wisconsin, and so according to the ranking assumption, they should have won all the states below it. They in fact lost Nevada, Colorado, and New Hampshire. So three errors for the ranking assumption. Ignoring Wisconsin, there was one error---the Democrats should not have won New Hampshire given that they lost Pennsylvania and Michigan. Note, however, that the ranking assumption did better than the betting markets. The Republicans won five elections that they were not favored to win: Wisconsin, Pennslyvania, Michigan, Florida, and North Carolina. For the first three the probabilities were 90 percent or above of the Republicans losing.

For the Senate election, the Republicans won Wisconsin, and so according to the ranking assumption, they should have won all the states below it. They in fact lost Nevada and New Hampshire. So two errors for the ranking assumption. Regarding the betting markets, the Republicans won two elections they were not favored to win: Wisconsin and Pennslyvania, which had probabilities of 84 and 79 percent, respectively, of the Democrats winning.

For the House election it is probably best just to focus on the 25 elections for which there are betting-market data. The Republicans won 186 Nebraska 2, and so according to the ranking assumption, they should have won all the elections below it. They in fact lost (using only the betting market data) 191 Florida 7, 196 New Jersey 5, and 198 Illinois 10. So three errors for the ranking assumption. Regarding the betting market, the Republicans won six elections that they were not favored to win: 186 Nebraska 2, 188 Texas 23, 192 Minnesota 2, 195 Virginia 10, 197 California 25, and 200 California 49. (The 0.501 probabilities in the table are really 50/50, and so these are not counted here.)

Ranking Assumption for 2016 Presidential election
Background

The paper, Interpreting the Predictive Uncertainty of Elections, Journal of Politics, April 2009, provides an interpretation of the uncertainty that exists on election morning as to who will win. The interpretation is based on the theory that there are a number of possible conditions of nature than can exist on election day, of which one is drawn. Political betting markets provide a way of trying to estimate this uncertainty. (Polling standard errors do not provide estimates of this type of uncertainty. They estimate sample-size uncertainty, which can be driven close to zero with a large enough sample.)

This paper also introduces a "ranking assumption," which puts restrictions on the possible conditions of nature that can exist on election day. Take as an example the vote in each state for the Democratic candidate for president. Rank the states by the probability on the day of the election that the candidate wins the state. The ranking assumption says that if the candidate wins state i, he or she wins every state ranked above state i.

Given some ranking, the ranking assumption can be tested by simply looking to see after the fact if the candidate won a state ranked lower than one he or she lost. In the paper the assumption was tested for the 2004 and 2008 presidential elections using Intrade probabilities at 6am Eastern standard time on the day of the election. The test is thus a test of the joint hypothesis that the Intrade probabilities on November 7, 2016, are right and the ranking assumption is right. Using the Intrade probabilities, the ranking assumption was perfect in 2004 and off by one in 2008. In 2008 Missouri was ranked above Indiana, and Obama won Indiana and lost Missouri. Both of these elections were very close. Obama won Indiana with 50.477 percent of the two-party vote and lost Missouri with 49.937 percent of the two-party vote. Otherwise, 2008 was perfect.

Evidence is also presented in the paper, although this is not a test of the ranking assumption, that Intrade traders used the ranking assumption to price various contracts.

2016 Presidential Election

I plan to collect market probabilities by state from PredictWise on various days, the last day being the day before the election, November 7, 2016. The November 7 data will be used to test the ranking assumption. The test is a test of the joint hypothesis that the PredictWise market probabilities are right and the ranking assumption is right. The data as they are collected are presented in Table 1.

Data collected from PredictWise on November 7, 2016, 9pm

These are the final data that will be used to test the ranking assumption. On this date, all but 10 states had market probabilities on the PredictWise website above 96 percent or below 10 percent. These states can be ignored. The 10 states, ranked by market probabilities for the Democratic candidate, are:

state prob votes actual sumvotes
WI 96+ 10 R 224
NV 95 6 D 230
CO 94 9 D 239
PA 94 20 R 259
MI 90 16 R 275 pivot
NH 89 4 D
FL 77 29 R
NC 61 15 R
OH 32 18 R
AZ 24 11 R
IA 15 6 R
89 = PredictWise market-based probability that Clinton wins the presidential election.

"sumvotes" is the sum of the electoral votes of all the states ranked above the state plus the state's vote. 270 votes are needed to win. Michigan is the pivot state, with a probablility of 90. All the states above Nevada in the ranking have probabilities greater than 95 (these are not shown). If Clinton takes Michigan and all the states ranked above it, she gets 275 votes. Of the states ranked below Michigan, she could also win by not taking Michigan but taking, say, Florida. This would, of course, violate the ranking assumption.

There is evidence that traders are essentially using the ranking assumption. According to the ranking assumption, the probability that Clinton wins overall is the probability that she wins the pivot state, Michigan, which is 90. On the PredictWise website, the market-based probability that Clinton wins the presidential election (in the electoral college) is 89, close to 90.

Table 1 gives more details.

Previous data collected

Ranking Assumption for 2016 Senate elections
Background

The ranking assumption can also be tested using data from the Senate elections. Consier the vote in each state for the Democratic candidate for Senate. Rank the states by the probability that the Democratic candidate wins the state. The ranking assumption says that if the Democrats win state i, they win every state ranked above state i.

The ranking assumption can thus be tested by simply looking to see after the fact if the Democrats won a state ranked lower than one they lost (contrary to the ranking assumption). I plan to collect market probabilities from PredictWise on various days, the last day being the day before the election, November 7, 2016. The November 7 data will be used to test the ranking assumption. Again, the test is a test of the joint hypothesis that the PredictWise market probabilities are right and the ranking assumption is right.

Data collected from PredictWise on November 7, 2016, 9pm

These are the final data that will be used to test the ranking assumption. The current make up of the Senate is 54 Republicans and 46 Democrats, counting the 2 independents as Democrats. Only 10 states are in play in having market probabilities on the PredictWise website less than 97 percent and greater than 10 percent. The 10 states ranked by the market probabilities from PredictWise for the Democratic candidate are:

state prob now actual
IL 96RD
WI 84RR
PA 79RR
NV 77DD
NH 57RD
MO 36RRpivot for 51 Democratic seats
NC 34RR
IN 29RR
FL 11RR
LA 13RR
67 = PredictWise market-based probability of the Democrats controlling the Senate.

If the Democrats win Missouri and all the states above it, they will have 51 seats, counting the 2 independents as Democrats. If they lose Missouri but win New Hampshire and all the states above it, they will have 50 seats. In this case they will still control the Senate if they win the White House. According to the ranking assumption, the PredictWise market probablility that they control the Senate is thus 57 percent (the probablity they win New Hampshire) if they win the White House and 36 percent (the probablility they win Missouri) if they don't. If we use the PredictWise market-based probabilty of 89 percent that Clinton wins the presidential electon, then the ranking assumption probability that the Democrats control the Senate is 0.89x57 + 0.11x36, which is 55.7 percent. This is considerably lower than the PredictWise market-based probability of the Democrats controlling the Senate of 67 percent.

Previous data collected

Ranking Assumption for 2016 House elections
Background

The ranking assumption can also be tested using data from the House elections. Consider the vote in each of the 435 districts for the Democratic candidate for the House. Rank the districts by the probability that the Democratic candidate wins the district. The ranking assumption says that if the Democrats win district i, they win every district ranked above district i. The ranking assumption can thus be tested by simply looking to see after the fact if the Democrats won a district ranked lower than one they lost (contrary to the ranking assumption).

The data for the House are not as good as the data for the Senate. From PredictWise one can get a ranking of the districts, but only 25 districts have betting markets. The probabilities for the other districts are just the views of PredictWise. The 25 betting markets are from Predictit. What I have done is to take the 25 probabilites from Predictit and the remaining probabilites from PredictWise. The final data were collected on November 7, 2016, 9pm. They are as follows. When the probability ends in 1, this is a Predictit probability; otherwise it is a PredictWise probability. (The Predictit probabilities are in fact only two digits; the 1 is just for presentation purposes.) 

 Rank      District                 Probability       Actual
   1  AL - Alabama        7           1.000
   2  AZ - Arizona        3           1.000
   3  AZ - Arizona        7           1.000
   4  CA - California        2        1.000
   5  CA - California        5        1.000
   6  CA - California        6        1.000
   7  CA - California        11       1.000
   8  CA - California        12       1.000
   9  CA - California        13       1.000
  10  WI - Wisconsin        4         1.000
  11  WI - Wisconsin        3         1.000
  12  WI - Wisconsin        2         1.000
  13  CA - California        14       1.000
  14  CA - California        15       1.000
  15  WA - Washington        9        1.000
  16  CA - California        17       1.000
  17  WA - Washington        7        1.000
  18  WA - Washington        6        1.000
  19  CA - California        18       1.000
  20  CA - California        19       1.000
  21  CA - California        20       1.000
  22  WA - Washington        2        1.000
  23  CA - California        27       1.000
  24  VT - Vermont        1           1.000
  25  VA - Virginia        11         1.000
  26  CA - California        28       1.000
  27  CA - California        29       1.000
  28  VA - Virginia        8          1.000
  29  CA - California        30       1.000
  30  CA - California        32       1.000
  31  CA - California        33       1.000
  32  CA - California        34       1.000
  33  VA - Virginia        3          1.000
  34  CA - California        35       1.000
  35  CA - California        37       1.000
  36  CA - California        38       1.000
  37  CA - California        40       1.000
  38  CA - California        41       1.000
  39  CA - California        43       1.000
  40  CA - California        44       1.000
  41  TX - Texas        35            1.000
  42  TX - Texas        34            1.000
  43  TX - Texas        33            1.000
  44  CA - California        46       1.000
  45  CA - California        47       1.000
  46  TX - Texas        30            1.000
  47  TX - Texas        29            1.000
  48  TX - Texas        28            1.000
  49  CA - California        51       1.000
  50  CA - California        53       1.000
  51  CO - Colorado        1          1.000
  52  CO - Colorado        2          1.000
  53  CT - Connecticut        1       1.000
  54  CT - Connecticut        2       1.000
  55  CT - Connecticut        3       1.000
  56  TX - Texas        20            1.000
  57  DE - Delaware        1          1.000
  58  TX - Texas        18            1.000
  59  FL - Florida        5           1.000
  60  TX - Texas        16            1.000
  61  FL - Florida        9           1.000
  62  FL - Florida        14          1.000
  63  FL - Florida        20          1.000
  64  FL - Florida        21          1.000
  65  FL - Florida        23          1.000
  66  FL - Florida        24          1.000
  67  TX - Texas        9             1.000
  68  GA - Georgia        2           1.000
  69  GA - Georgia        4           1.000
  70  GA - Georgia        5           1.000
  71  GA - Georgia        13          1.000
  72  HI - Hawaii        1            1.000
  73  HI - Hawaii        2            1.000
  74  IL - Illinois        1          1.000
  75  IL - Illinois        2          1.000
  76  TN - Tennessee        9         1.000
  77  IL - Illinois        3          1.000
  78  IL - Illinois        4          1.000
  79  IL - Illinois        5          1.000
  80  TN - Tennessee        5         1.000
  81  IL - Illinois        7          1.000
  82  IL - Illinois        9          1.000
  83  IL - Illinois        11         1.000
  84  IL - Illinois        17         1.000
  85  IN - Indiana        1           1.000
  86  IN - Indiana        7           1.000
  87  SC - South Carolina        6    1.000
  88  KY - Kentucky        3          1.000
  89  LA - Louisiana        2         1.000
  90  MA - Massachusetts        1     1.000
  91  MA - Massachusetts        2     1.000
  92  MA - Massachusetts        3     1.000
  93  RI - Rhode Island        2      1.000
  94  RI - Rhode Island        1      1.000
  95  MA - Massachusetts        4     1.000
  96  MA - Massachusetts        5     1.000
  97  MA - Massachusetts        7     1.000
  98  MA - Massachusetts        8     1.000
  99  PA - Pennsylvania        14     1.000
 100  PA - Pennsylvania        13     1.000
 101  MD - Maryland        2          1.000
 102  MD - Maryland        3          1.000
 103  MD - Maryland        4          1.000
 104  MD - Maryland        5          1.000
 105  MD - Maryland        7          1.000
 106  MD - Maryland        8          1.000
 107  ME - Maine        1             1.000
 108  MI - Michigan        5          1.000
 109  MI - Michigan        9          1.000
 110  MI - Michigan        12         1.000
 111  PA - Pennsylvania        2      1.000
 112  PA - Pennsylvania        1      1.000
 113  MI - Michigan        13         1.000
 114  MI - Michigan        14         1.000
 115  OR - Oregon        3            1.000
 116  MN - Minnesota        4         1.000
 117  OR - Oregon        1            1.000
 118  MN - Minnesota        5         1.000
 119  MO - Missouri        1          1.000
 120  MO - Missouri        5          1.000
 121  MS - Mississippi        2       1.000
 122  NC - North Carolina      1      1.000
 123  NC - North Carolina      4      1.000
 124  NC - North Carolina      12     1.000
 125  NJ - New Jersey        1        1.000
 126  OH - Ohio        13             1.000
 127  NJ - New Jersey        6        1.000
 128  OH - Ohio        11             1.000
 129  NJ - New Jersey        8        1.000
 130  OH - Ohio        9              1.000
 131  NJ - New Jersey        9        1.000
 132  NJ - New Jersey        10       1.000
 133  NJ - New Jersey        12       1.000
 134  NM - New Mexico        1        1.000
 135  NM - New Mexico        3        1.000
 136  OH - Ohio        3              1.000
 137  NV - Nevada        1            1.000
 138  NY - New York        5          1.000
 139  NY - New York        6          1.000
 140  NY - New York        26         1.000
 141  NY - New York        7          1.000
 142  NY - New York        8          1.000
 143  NY - New York        9          1.000
 144  NY - New York        10         1.000
 145  NY - New York        12         1.000
 146  NY - New York        20         1.000
 147  NY - New York        13         1.000
 148  NY - New York        14         1.000
 149  NY - New York        15         1.000
 150  NY - New York        16         1.000
 151  CA - California        9        0.990
 152  NY - New York        17         0.990
 153  WA - Washington        10       0.990
 154  CA - California        16       0.990
 155  WA - Washington        1        0.990
 156  CA - California        31       0.990
 157  CO - Colorado        7          0.990
 158  CT - Connecticut        4       0.990
 159  CT - Connecticut        5       0.990
 160  TX - Texas        15            0.990
 161  FL - Florida        22          0.990
 162  NY - New York        4          0.990
 163  IA - Iowa        2              0.990
 164  IL - Illinois        8          0.990
 165  PA - Pennsylvania        17     0.990
 166  MA - Massachusetts        6     0.990
 167  MA - Massachusetts        9     0.990
 168  OR - Oregon        5            0.990
 169  OR - Oregon        4            0.990
 170  NH - New Hampshire        2     0.990
 171  AZ - Arizona        9           0.980
 172  CA - California        3        0.980
 173  CA - California        26       0.980
 174  CA - California        52       0.980
 175  CA - California        36       0.970
 176  MN - Minnesota        1         0.970
 177  NY - New York        18         0.960
 178  NV - Nevada        4            0.940
 179  MN - Minnesota        7         0.920
 180  NY - New York        25         0.910
 181  CA - California        7        0.881 betting
 182  VA - Virginia        4          0.880
 183  MD - Maryland        6          0.870
 184  NH - New Hampshire        1     0.870
 185  FL - Florida        10          0.840          D and all above
 186  NE - Nebraska        2          0.801 betting  R
 187  FL - Florida        13          0.80           D
 188  TX - Texas        23            0.781 betting  R
 189  IA - Iowa        1              0.770          R
 190  CA - California        24       0.750          D
 191  FL - Florida        7           0.711 betting  D
 192  MN - Minnesota        2         0.691 betting  R
 193  NY - New York        3          0.680          D
 194  NV - Nevada        3            0.590          D
 195  VA - Virginia        10         0.571 betting  R
 196  NJ - New Jersey        5        0.561 betting  D
 197  CA - California        25       0.551 betting  R
 198  IL - Illinois        10         0.551 betting  D
 199  MN - Minnesota        8         0.530          D
 200  CA - California        49       0.521 betting  R
 201  CA - California        10       0.501 betting  R
 202  CO - Colorado        6          0.501 betting  R
 203  FL - Florida        26          0.501 betting  R
 204  AZ - Arizona        1           0.490          D
 205  CA - California        21       0.430          R and all below
 206  NY - New York        19         0.411 betting 
 207  FL - Florida        18          0.371 betting 
 208  PA - Pennsylvania        8      0.371 betting 
 209  ME - Maine        2             0.341 betting 
 210  MI - Michigan        8          0.320
 211  AZ - Arizona        2           0.300
 212  IL - Illinois        12         0.290
 213  MI - Michigan        1          0.271 betting 
 214  PA - Pennsylvania        16     0.261 betting 
 215  PA - Pennsylvania        6      0.230
 216  MN - Minnesota        3         0.220
 217  VA - Virginia        5          0.200
 218  NY - New York        1          0.191 betting, pivot for Democratic control
 219  NY - New York        21         0.190
 220  MI - Michigan        7          0.190
 221  WI - Wisconsin        8         0.161 betting 
 222  NY - New York        22         0.161 betting 
 223  KS - Kansas        3            0.160
 224  IN - Indiana        9           0.150
 225  UT - Utah        4              0.111 betting 
 226  IA - Iowa        3              0.111 betting 
 227  NY - New York        23         0.110
 228  VA - Virginia        2          0.100
 229  MT - Montana        1           0.100
 230  AK - Alaska        1            0.090
 231  CO - Colorado        3          0.090
 232  IN - Indiana        2           0.080
 233  NY - New York        24         0.051 betting 
 234  NJ - New Jersey        3        0.050
 235  NY - New York        11         0.040
 236  NC - North Carolina      13     0.040
 237  IL - Illinois        13         0.040
 238  MI - Michigan        6          0.040
 239  NJ - New Jersey        2        0.030
 240  FL - Florida        2           0.030
 241  WI - Wisconsin        7         0.020
 242  PA - Pennsylvania        7      0.020
 243  NC - North Carolina      2      0.020
 244  WI - Wisconsin        6         0.020
 245  WA - Washington        8        0.020
 246  MI - Michigan        3          0.020
 247  WA - Washington        3        0.020
 248  MI - Michigan        11         0.020
 249  AR - Arkansas        2          0.010
 250  PA - Pennsylvania        12     0.010
 251  WV - West Virginia        2     0.010
 252  MI - Michigan        4          0.010
 253  NJ - New Jersey        7        0.010
 254  OH - Ohio        10             0.010
 255  WI - Wisconsin        1         0.010
 256  WA - Washington        5        0.010
 257  NJ - New Jersey        11       0.010
 258  MI - Michigan        10         0.010
 259  OH - Ohio        6              0.010
 260  OH - Ohio        16             0.010
 261  OH - Ohio        14             0.010
 262  NM - New Mexico        2        0.010
 263  FL - Florida        15          0.010
 264  FL - Florida        16          0.010
 265  GA - Georgia        12          0.010
 266  NY - New York        2          0.010
 267  OH - Ohio        1              0.010
 268  IA - Iowa        4              0.010
 269  IL - Illinois        6          0.010
 270  SC - South Carolina        7    0.010
 271  SC - South Carolina        5    0.010
 272  KS - Kansas        2            0.010
 273  MO - Missouri        6          0.000
 274  OR - Oregon        2            0.000
 275  IN - Indiana        8           0.000
 276  KS - Kansas        1            0.000
 277  IN - Indiana        6           0.000
 278  IN - Indiana        5           0.000
 279  IN - Indiana        4           0.000
 280  IN - Indiana        3           0.000
 281  MO - Missouri        7          0.000
 282  OH - Ohio        8              0.000
 283  IL - Illinois        18         0.000
 284  SD - South Dakota        1      0.000
 285  IL - Illinois        16         0.000
 286  IL - Illinois        15         0.000
 287  IL - Illinois        14         0.000
 288  MO - Missouri        3          0.000
 289  MO - Missouri        4          0.000
 290  TN - Tennessee        1         0.000
 291  NC - North Carolina      5      0.000
 292  TN - Tennessee        2         0.000
 293  MN - Minnesota        6         0.000
 294  TN - Tennessee        3         0.000
 295  KS - Kansas        4            0.000
 296  TN - Tennessee        4         0.000
 297  TN - Tennessee        6         0.000
 298  TN - Tennessee        7         0.000
 299  TN - Tennessee        8         0.000
 300  TX - Texas        1             0.000
 301  ID - Idaho        2             0.000
 302  ID - Idaho        1             0.000
 303  KY - Kentucky        1          0.000
 304  KY - Kentucky        2          0.000
 305  SC - South Carolina        4    0.000
 306  ND - North Dakota        1      0.000
 307  TX - Texas        2             0.000
 308  TX - Texas        3             0.000
 309  GA - Georgia        14          0.000
 310  TX - Texas        4             0.000
 311  KY - Kentucky        4          0.000
 312  GA - Georgia        11          0.000
 313  GA - Georgia        10          0.000
 314  GA - Georgia        9           0.000
 315  GA - Georgia        8           0.000
 316  GA - Georgia        7           0.000
 317  GA - Georgia        6           0.000
 318  TX - Texas        5             0.000
 319  TX - Texas        6             0.000
 320  GA - Georgia        3           0.000
 321  TX - Texas        7             0.000
 322  GA - Georgia        1           0.000
 323  FL - Florida        27          0.000
 324  PA - Pennsylvania        3      0.000
 325  FL - Florida        25          0.000
 326  TX - Texas        8             0.000
 327  TX - Texas        10            0.000
 328  NC - North Carolina      10     0.000
 329  TX - Texas        11            0.000
 330  TX - Texas        12            0.000
 331  FL - Florida        19          0.000
 332  MS - Mississippi        1       0.000
 333  FL - Florida        17          0.000
 334  KY - Kentucky        5          0.000
 335  KY - Kentucky        6          0.000
 336  TX - Texas        13            0.000
 337  NE - Nebraska        3          0.000
 338  FL - Florida        12          0.000
 339  FL - Florida        11          0.000
 340  LA - Louisiana        1         0.000
 341  TX - Texas        14            0.000
 342  FL - Florida        8           0.000
 343  SC - South Carolina        3    0.000
 344  FL - Florida        6           0.000
 345  NY - New York        27         0.000
 346  FL - Florida        4           0.000
 347  FL - Florida        3           0.000
 348  OK - Oklahoma        3          0.000
 349  FL - Florida        1           0.000
 350  TX - Texas        17            0.000
 351  NJ - New Jersey        4        0.000
 352  PA - Pennsylvania        4      0.000
 353  TX - Texas        19            0.000
 354  TX - Texas        21            0.000
 355  TX - Texas        22            0.000
 356  NV - Nevada        2            0.000
 357  LA - Louisiana        3         0.000
 358  CO - Colorado        5          0.000
 359  CO - Colorado        4          0.000
 360  OK - Oklahoma        5          0.000
 361  NE - Nebraska        1          0.000
 362  TX - Texas        24            0.000
 363  TX - Texas        25            0.000
 364  LA - Louisiana        4         0.000
 365  TX - Texas        26            0.000
 366  CA - California        50       0.000
 367  NC - North Carolina      3      0.000
 368  CA - California        48       0.000
 369  TX - Texas        27            0.000
 370  TX - Texas        31            0.000
 371  CA - California        45       0.000
 372  TX - Texas        32            0.000
 373  TX - Texas        36            0.000
 374  CA - California        42       0.000
 375  UT - Utah        1              0.000
 376  UT - Utah        2              0.000
 377  CA - California        39       0.000
 378  UT - Utah        3              0.000
 379  OH - Ohio        2              0.000
 380  OH - Ohio        7              0.000
 381  VA - Virginia        1          0.000
 382  LA - Louisiana        5         0.000
 383  PA - Pennsylvania        5      0.000
 384  NC - North Carolina      7      0.000
 385  NC - North Carolina      11     0.000
 386  VA - Virginia        6          0.000
 387  VA - Virginia        7          0.000
 388  VA - Virginia        9          0.000
 389  NC - North Carolina      8      0.000
 390  LA - Louisiana        6         0.000
 391  NC - North Carolina      6      0.000
 392  MI - Michigan        2          0.000
 393  CA - California        23       0.000
 394  CA - California        22       0.000
 395  MS - Mississippi        3       0.000
 396  OK - Oklahoma        4          0.000
 397  MD - Maryland        1          0.000
 398  WA - Washington        4        0.000
 399  SC - South Carolina        2    0.000
 400  PA - Pennsylvania        11     0.000
 401  PA - Pennsylvania        10     0.000
 402  OK - Oklahoma        1          0.000
 403  SC - South Carolina        1    0.000
 404  WI - Wisconsin        5         0.000
 405  PA - Pennsylvania        9      0.000
 406  MO - Missouri        8          0.000
 407  PA - Pennsylvania        18     0.000
 408  CA - California        8        0.000
 409  MO - Missouri        2          0.000
 410  OH - Ohio        12             0.000
 411  OH - Ohio        15             0.000
 412  CA - California        4        0.000
 413  OH - Ohio        5              0.000
 414  WV - West Virginia        1     0.000
 415  CA - California        1        0.000
 416  OH - Ohio        4              0.000
 417  AZ - Arizona        8           0.000
 418  NC - North Carolina      9      0.000
 419  AZ - Arizona        6           0.000
 420  AZ - Arizona        5           0.000
 421  AZ - Arizona        4           0.000
 422  WV - West Virginia        3     0.000
 423  OK - Oklahoma        2          0.000
 424  MS - Mississippi        4       0.000
 425  AR - Arkansas        4          0.000
 426  AR - Arkansas        3          0.000
 427  PA - Pennsylvania        15     0.000
 428  AR - Arkansas        1          0.000
 429  WY - Wyoming        1           0.000
 430  AL - Alabama        6           0.000
 431  AL - Alabama        5           0.000
 432  AL - Alabama        4           0.000
 433  AL - Alabama        3           0.000
 434  AL - Alabama        2           0.000
 435  AL - Alabama        1           0.000
You can see that the pivot is the 1st district of New York with a probability of 0.19. If the Democrats win this district and all the districts above it, they have control of the House. According to the ranking assumption, the probabiity of this happening is 0.19.

On the Predictit website the betting probability that the Democrats get 218 or more seats was 0.065 (at 9pm, November 7, 2016). This compares to 0.19 using the ranking assumption.

Previous data collected

Tests using the 2012 Presidential Election and the 2014 Senate Elections
2012 and 2014 Elections