| Congressional Prediction for 2014: October 30, 2014 |
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The equation used to predict the Democratic share of the two-party House vote
in 2014 is equation 3a in Table 2 in
Presidential and Congressional
Vote-Share Equations: November 2010 Update.
All the right hand side variables in this equation are known
except the inflation
variable and the good news variable. The
Democratic share of the two-party presidential vote in 2012 was 52.0,
and the Democratic share of the two-party House vote in 2012 was 50.68.
Given these values, given the constant term in equation 3a, and
given the value of variable I of 1, equation 3a can be written:
VOTECC = 48.53 - .482*INFLATIONCC + .710*(15/7)*GOODNEWSCC where VOTECC is the Democratic share of the two-party House vote in 2014, INFLATIONCC is the growth rate of the GDP deflator in the first 7 quarters of the second Obama administration, 2013:1-2014:3, at an annual rate, and GOODNEWSCC is the number of quarters in the first 7 quarters of the Obama administration in which the growth rate of real per capita GDP is greater than 3.2 percent at an annual rate. Using the forecasts of August 5, 2013, November 11, 2013, January 30, 2014, April 30, 2014, and July 31, 2014, from the US model and the actual data on October 30, 2014, the predictions for VOTECC are:
INFLATIONCC GOODNEWSCC VOTECC
August 5, 2013 2.2 4 53.56
November 11, 2013 1.9 1 49.14
January 30, 2014 1.8 3 52.23
April 30, 2014 1.7 2 50.75
July 31, 2014 1.6 2 50.80
October 30, 2014 1.5 2 50.85
October 30, 2014 All of the economic data before the election are now known. Two of the 7 quarters are good news quarters, 2013:3 and 2014:2. The percentage change in the GDP deflator over the seven quarters at an annual rate is 1.5 percent. These values lead to a predicted Democratic vote share of 50.85 percent. The election is thus continuing to be predicted to be very close regarding the two-party vote share in the House. July 31, 2014 As of July 31, 2014, only one quarter is not known, 2014:3. Two of the known 6 quarters are good news quarters, 2013:3 and 2014:2, and 2014:3 is not forecast to be a good news quarter. There are thus a total of 2 good news quarters. With this prediction and with the inflation prediction of 1.6 percent, the predicted Democratic vote share is 50.80 percent. The election is thus predicted to be very close. April 30, 2014 The April 30, 2014, forecast has 2 good news quarters, down 1 from the January 30, 2014, forecast. The inflation prediction is about the same (1.7 percent versus 1.8 percent). The predicted Democratic vote share falls from 52.23 to 50.75. The election is thus predicted to be very close. January 30, 2014 The January 30, 2014, forecast has 3 good news quarters, up from 1 for the November 11, 2013, forecast, and this increases the Democratic vote share from 49.14 to 52.23. The election still looks close, with a slight edge for the Democrats if the economy in fact grows in the first three quarters of 2014 as much as the US model is currently forecasting. November 11, 2013 The August 5, 2013, forecast from the US model was very optimistic about the economy for the last half of 2013 and for 2014, with 4 good news quarters. The November 11, 2013, forecast is much less so, with only 1 good news quarter, the third quarter of 2014. The predicted vote share is now 49.14, a slight Democratic loss. The main conclusion is the same as it was in August, namely that if the economy grows moderately, the election is predicted to be close. August 5, 2013 The August 5, 2013, forecast from the US model is much more optimistic about the rest of 2013 and 2014 than is the consensus view. Remember that it is more a baseline forecast than one to be taken as a final version. This forecast has 4 strong growth quarters, and given this, the predicted two-party vote share for the Democrats in the House in 2014 is 53.56 percent. If, however, there were to be only 1 strong growth quarter, the predicted share would be only 48.99. The story from the equation is thus if the economy is very strong between now and November 2014, the Democrats are predicted to do well. If the economy only grows moderately, the election is predicted to be close. I do not have an equation that translates the vote share into House seats, and so I have no prediction of House seats. If you want to compute your own prediction of the vote share using different assumptions about the economy, go to: |
| Post Mortem: November 7, 2012 |
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It looks like the two-party vote share for Obama will be about 51.3 percent.
The last prediction of the vote equation below (dated October 26, 2012) was
49.0 percent, which is an error of 2.3 percentage points. The standard error
of the equation is 2.5, and so the actual error is about equal to the
standard error. An error this small
means that when I reestimate the vote equation with
the 2012 election added, the coefficient estimates are not likely to change
much. There is nothing in the 2012 results that cast doubt on the
specification of the equation. It is too early to get data on VC, the
Democratic share of the two-party House vote. |
| Vote-Share Equations: November 2010 Update |
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Background:
The paper,
Presidential and Congressional
Vote-Share Equations: November 2010 Update, discusses the
November 2010 update of the vote-share equations. Forecasts for
2012 are also made.
This discussion assumes that the paper,
Presidential and Congressional
Vote-Share Equations, American Journal of Political Science,
January 2009, 55-72, has been read.
Compute your own prediction: The following link allows you to compute your own predictions of the 2012 presidential and House elections. Compute your own predictions for 2012
Predictions: The current and past predictions of VP and VC using the economic forecasts from the US model are:
G P Z VP VC
November 11, 2010 3.69 1.42 6 55.9 49.9
January 29, 2011 1.93 1.77 4 52.5 48.0
April 28, 2011 2.69 2.01 4 52.8 48.2
July 31, 2011 3.64 2.06 4 53.4 48.5
October 30, 2011 2.75 1.88 1 50.0 46.6
January 28, 2012 2.88 1.54 1 50.3 46.7
April 27, 2012 2.95 1.78 1 50.2 46.7
July 27, 2012 1.62 1.51 1 49.5 46.3
October 26, 2012 1.03 1.57 1 49.0 46.0
October 26, 2012, comment: This is the last vote prediction before
the election. Given the NIPA third-quarter data that were released today,
the value of G is 1.03, the value of P is 1.57, and the value of Z is still 1.
The predicted two-party vote share for Obama is 49.0 percent (VP), and the
predicted two-party vote share in the House for the Democrats is
46.0 percent (VC). The presidential election is thus predicted to be
very close regarding vote share, as it has been since October of last year.
Obama has lost 1.0 percentage points of vote share between October 30, 2011,
and now. The growth rate in the first three quarters of this year (G) turned
out to be smaller than was predicted last October, as also did
the inflation rate variable (P). The smaller G lowers the
predicted vote share, and the smaller P raises it. On net, the predicted
vote share fell 1.0 percentage points. The standard error of the vote-share
equation is at least 2.5 percentage points (see the November 2010 update
above), and so 50.0 percent is well within a one standard deviation error
band centered at 49.0. The present results thus have a very limited amount
to say about the likely winner of the presidential election. This is
especially true in the current election because it could be that Obama loses
the popular vote but wins in the electoral college.
July 27, 2012, comment: The NIPA data have been revised back to 2009, and the current forecast incorporates these revisions. Only one more quarter of unknown economic data is left (the third quarter of 2012), and so most of the economic information is in. The latest economic forecast from the US model (dated July 27, 2012) has a (non per capita) growth rate in this quarter of 3.4 percent and an inflation rate of 2.1 percent. (All growth rates in this comment are at annual rates.) Using these values and the known actual values leads to a value of G of 1.62 percent, a value of P of 1.51 percent, and a value of Z of 1. (The one good news quarter is the fourth quarter of 2011.) (Population growth in the third quarter of 2012 is assumed to be 0.67 percent at an annual rate, which is the actual annual rate for the first and second quarters of 2012.) Comparing the April 27, 2012, prediction with the July 27, 2012, prediction, the lower growth rate hurt Obama and the lower inflation rate helped. On net, the predicted two-party vote share for the Democrats (VP) fell from 50.2 percent to 49.5 percent. The main message, however, is the same as it has been since October 30, 2011, namely that the election is too close to call. The ex ante standard error is around 3 percent---see Table 5 in Presidential and Congressional Vote-Share Equations: November 2010 Update---and a predicted loss for the Democrats of 0.5 percentage points is well within this standard error. If the election is in fact close, the vote equation will have done well. If one of the two candidates wins by a fairly large amount, it will not have done well. April 27, 2012, comment: The April 27, 2012, forecast from the US model is not very different from the January 28, 2012, forecast. G is now 2.95 rather than 2.88, P is now 1.78 rather than 1.54, and Z is still 1. (The (predicted) one strong growth quarter is still 2012:3.) The new economic values lead to a predicted value of VP of 50.2, essentially the same as the 50.3 in October. The predicted value of VC is still 46.7 rounded to one decimal point. As noted in the previous comment, the main message from the presidential vote equation is the same as it has been from the beginning. For a moderately growing economy the election is predicted to be close. The current US model forecast is more optimistic than consensus, but with somewhat slower growth in 2012 the election would still be predicted to be close, which you can experiment with by computing your own vote prediction---see below. (Remember that one standard error is at least 2.5 percentage points.) Unless there is an expected boom or bust in the economy between now and November, this message will stay the same. January 28, 2012, comment: The January 28, 2012, forecast from the US model is not that different from the October 30, 2011, forecast. G is now 2.88 rather than 2.75, P is now 1.54 rather than 1.88, and Z is still 1. (The one strong growth quarter is 2012:3.) The new economic values lead to a predicted value of VP of 50.30, essentially the same as the 50.0 in October. The predicted value of VC is now 46.7 rather than 46.6 in October. The main message from the presidential vote equation is again the same as it has been from the beginning. For a moderately growing economy, which the US model is now forecasting, the election is predicted to be close. The current US model forecast is probably somewhat more optimistic than consensus, but with slightly slower growth in 2012, the election would still be predicted to be close. If the economy suddenly starts to boom---say 5 or 6 percent growth---Obama would be predicted to win by a comfortable amount. If the economy suddenly goes into another recession---say minus 5 or 6 percent growth---the Republicans would be predicted to win by a comfortable amount. As of this writing the economy in 2012 looks like it will be ok, but not great, which means a close election---essentially too close to call. If the economy does turn out to be ok, but not great, and if the election is close, the voting equation will have done well. If instead in this case the election is not close, the equation will have made a large error. Payroll tax comment, January 28, 2012: The above economic forecast (January 28, 2012) assumes that the payroll tax cuts are extended through 2012 rather than only through the first two months of 2012, as currently legislated. If the cuts are not extended, the US model estimates that G will be smaller by 0.51 (2.37 instead of 2.88) and Z will be zero (2012:3 is no longer a strong growth quarter). P is roughly the same. These new values of G and Z lead to a predicted vote share for Obama of 49.0, down from 50.3. Not extending the payroll tax cuts is thus estimated to cost Obama 1.3 percentage points of vote share. The election is still, of course, predicted to be close. Finally, the above economic forecast did not assume that unemployment benefits would be extended through 2012, as has been proposed. If they are in fact extended, this will increase G slightly and thus Obama's predicted vote share slightly. October 30, 2011, comment: The October 30, 2011, forecast from the US model is somewhat less optimistic about future output growth than was the July 31, 2011, forecast. G is now 2.75 rather than 3.64, and Z is now 1 rather than 4. (The one good news quarter is 2012:3.) P is slightly lower at 1.88 versus 2.06 before. The new economic values lead to a predicted value of VP of 50.0, down from 53.4 in July. The predicted value of VC has fallen from 48.5 to 46.6. The message from the presidential vote equation does not, of course, change. For a moderately growing economy, which the US model is now forecasting, the election is predicted to be close. If the economy does considerably better, which the US model was forecasting earlier, Obama is predicted to win, although the election is still fairly close. If the economy goes into another recession, Obama is predicted to lose. July 31, 2011, comment: Comparing the July and April predictions, VP has increased from 52.8 to 53.4 percent. This is because G has increased by about 1 percentage point---the US model is forecasting strong growth in 2012. The NIPA data revisions that were released on July 29, 2011, now show no good new quarters so far in the Obama administration (compared to one before), but Z is still 4 because the July 31 economic forecast has four good news quarters---2011:4, 2012:1, 2012:2, 2012:3---compared to three before. The prediction of an Obama victory with 53.4 percent of the two-party vote is conditional on the assumption that there will be strong growth between now and the election. According to the July 31 forecast from the US model, by election time the economy will have been growing well for five consecutive quarters, with the unemployment rate down to 7.9 percent. The economy will have turned around, and the vote equation predicts a victory for the incumbent party. Most current economic forecasts are, however, much less optimistic than this, and with a weaker economy the message from the vote equation is different. Say the economy grows at an annual rate of only 3 percent between now and the election, where there are no good news quarters and G is 2 percent. Using G = 2.0, P = 2.06, and Z = 0, the predicted value of VP is 48.4 percent, a narrow Republican victory. The economy is thus crucial according to the vote equation. A strong rebound results in a fairly solid Obama victory; a moderate to slightly below moderate economy results in a close election with an edge for the Republicans; and a double dip recession with, say, negative growth in 2012, results in a fairly solid Republican victory. April 28, 2011, comment: Comparing the April and January economic predictions, both G and P increased slightly, with the G change the larger. This led to a slight increase in the predicted vote shares for the Democrats. The main message from January, however, has not changed. January 29, 2011, comment: The latest economic prediction has more growth in 2011 and less growth in 2012 than the previous economic prediction had. It also has two fewer good news quarters. This results in the prediction for Obama falling from 55.9 to 52.5 percent and the prediction for the House Democrats falling from 49.9 to 48.0 percent.
Data for downloading:
Original paper:
Previous update papers:
Non technical discussions:
Web site material for previous elections:
Related work:
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