|Post Mortem: November 7, 2012|
|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|
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 46.0October 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:
Previous update papers:
Web site material for previous elections: