Farewell 2018 - Vic Review

Final, we have the Victorian election to review. 88 Legislative Assembly seats and 40 Legislative Council seats were up for election: the full Victorian parliament.

Legislative Assembly

74 seats, or 84.1%, were predicted correctly.

Seat	Prediction	Result
Albert Park	ALP	ALP
Altona	ALP	ALP
Bass	LIB	ALP
Bayswater	LIB	ALP
Bellarine	ALP	ALP
Benambra	LIB	LIB
Bendigo East	ALP	ALP
Bendigo West	ALP	ALP
Bentleigh	ALP	ALP
Box Hill	LIB	ALP
Brighton	LIB	LIB
Broadmeadows	ALP	ALP
Brunswick	ALP	GRN
Bulleen	LIB	LIB
Bundoora	ALP	ALP
Buninyong	ALP	ALP
Burwood	ALP	ALP
Carrum	ALP	ALP
Caulfield	LIB	LIB
Clarinda	ALP	ALP
Cranbourne	ALP	ALP
Croydon	LIB	LIB
Dandenong	ALP	ALP
Eildon	ALP	LIB
Eltham	ALP	ALP
Essendon	ALP	ALP
Euroa	NAT	NAT
Evelyn	LIB	LIB
Ferntree Gully	LIB	LIB
Footscray	ALP	ALP
Forest Hill	LIB	LIB
Frankston	ALP	ALP
Geelong	ALP	ALP
Gembrook	LIB	LIB
Gippsland East	NAT	NAT
Gippsland South	NAT	NAT
Hastings	LIB	LIB
Hawthorn	LIB	ALP
Ivanhoe	ALP	ALP
Kew	LIB	LIB
Keysborough	ALP	ALP
Kororoit	ALP	ALP
Lara	ALP	ALP
Lowan	NAT	NAT
Macedon	ALP	ALP
Malvern	LIB	LIB
Melbourne	ALP	GRN
Melton	ALP	ALP
Mildura	NAT	IND
Mill Park	ALP	ALP
Monbulk	ALP	ALP
Mordialloc	ALP	ALP
Mornington	LIB	LIB
Morwell	ALP	IND
Mount Waverley	LIB	ALP
Mulgrave	ALP	ALP
Murray Plains	NAT	NAT
Narracan	LIB	LIB
Narre Warren North	ALP	ALP
Narre Warren South	ALP	ALP
Nepean	LIB	ALP
Niddrie	ALP	ALP
Northcote	GRN	ALP
Oakleigh	ALP	ALP
Ovens Valley	NAT	NAT
Pascoe Vale	ALP	ALP
Polwarth	LIB	LIB
Prahran	GRN	GRN
Preston	ALP	ALP
Richmond	ALP	ALP
Ringwood	LIB	ALP
Ripon	ALP	LIB
Rowville	LIB	LIB
Sandringham	LIB	LIB
Shepparton	IND	IND
South Barwon	ALP	ALP
South-West Coast	LIB	LIB
St Albans	ALP	ALP
Sunbury	ALP	ALP
Sydenham	ALP	ALP
Tarneit	ALP	ALP
Thomastown	ALP	ALP
Warrandyte	LIB	LIB
Wendouree	ALP	ALP
Werribee	ALP	ALP
Williamstown	ALP	ALP
Yan Yean	ALP	ALP
Yuroke	ALP	ALP

The 14 incorrect predictions were:

Seat	Prediction	Result
Bass	LIB	ALP
Bayswater	LIB	ALP
Box Hill	LIB	ALP
Brunswick	ALP	GRN
Eildon	ALP	LIB
Hawthorn	LIB	ALP
Melbourne	ALP	GRN
Mildura	NAT	IND
Morwell	ALP	IND
Mount Waverley	LIB	ALP
Nepean	LIB	ALP
Northcote	GRN	ALP
Ringwood	LIB	ALP
Ripon	ALP	LIB

Mildura and Morwell saw independents elected. Because it is not feasible to look into the prospects of every independent running in every seat, I accepted long ago that upsets of this nature are unpredictable in practical terms.

I had also noted at the foot of my predictions that, for unempirical reasons, I expected the greens to pick up a few seats not officially predicted, and singled out Melbourne as likely to be retained. I do not consider Melbourne or Brunswick to be surprises.

Eildon and Ripon were retained by Liberal incumbents against the swing and remain very narrow as a result. ABC has Ripon held by the Liberal party with 50.0% of the final count, meaning there were only a handful of ballots between the major parties in the end. Eildon is a little less precarious, but with 52.4% of the vote we came very close to being right in both cases, and I think these are acceptable mistakes.

Northcote was held by the Greens, but only as the result of a by-election, the Liberals did not contest. I do not think the lack of Liberal contest in that by-election makes that data unreliable, as traditional liberal voters would have allocated their votes exactly as their preferences in a contested election. However, the by-election may have been atypical for the focus it provided on local issues. The Greens certainly still poll well here, but despite the ABC indicating a swing in their favour (compared to the general election, not the by-election) they did finish second. I am in two minds as to whether this is a reason to be more cautious with by-election data and incumbents or just part of the usual statistical hurley-burley.

The remaining seven seats (Bass, Bayswater, Box Hill, Hawthorn, Mount Waverley, Nepean and Ringwood) are evidence that I underestimated the swing to the ALP in this election. It is true that this swing was far higher than most predicted, but being wrong en mass is little consolation. Previous work on predicting the size and distribution of swings is required, though past efforts have provided little encouragement. Nevertheless, these are seven seats out of 88, and a mid-80% accuracy overall is both typical and acceptable.

Legislative Council

The LegCo results were more chaotic by far.

As with all proportional, preferential votes, the final member from each division is always unpredictable, so the districts with scores of 4/5 are perfectly acceptable to me despite the patchwork of colours in the infographic above.

The total prediction score of 30/40 or 75% would be disappointing in a race of single-member seats like the Legislative Assembly, but this inherently difficult fifth-member prediction means a score above 80% would be outstanding. The remaining 20% are inevitably written off in almost every case as tossups for the same reason seats won by independents are not considered particularly concerning in the lower houses.

The areas of concern, then, are the Southern Metropolitan district and both the Northern and Western regional districts.

In South Metro, the ALP gained from the Greens, and the Reason Party (formerly the Australian Sex Party) took the scraps from both sides to earn the 5th seat. This is the first time a party outside of the major trio (ALP, LIB and GRN) have won a seat in South Metro and though they did get a mention in the prediction, this is unexpected based on the earlier polling. Similarly, for the Greens to consistently poll 90% of a quota historically would seem to guarantee them a seat, but this year they were closer to 77%. Both errors here demonstrate that historical data makes for poor predictions of the future, though the absence of alternative numbers is an issue we will struggle to overcome.

In the regional districts, the Liberals lost ground to several minor parties too--a cause of errors in the 5th seat of other districts also (Metro East and Metro South East in particular). Again, this is the errors of past data being used predictively. It is evident the Liberals' support from previous years was not present in 2018. One predicted shooters seat in Vic West was also lost as part of the general uncertainty and minor-party chaos of the 5th post, but I'm more impressed that I called them correctly in Vic East (and got a full 5/5 in that district).

The lessons of the Legislative Council predictions then are that tossups should be used liberally if this blog still handed those out, and that past data is poor predictively but more or less all that was available.

Farewell 2018 - US review

The holiday season can no longer distract me from my responsibility to summarise the past two elections discussed on this blog. The first is the US Mid-Terms, where predictions were made for the House, the Senate and the Gubernatorial races.

The House

The methodology applied in the House predictions can be found here, but in brief it awarded uncontested elections and the widely accepted safe-rated seats to their presumed winners, then seats with a 2% polling margin, then an aggregation of available data including polling, predicted swings and third-party assessments.

The results are as follows:

District	Prediction	Result
Alabama 1st	Republican	Republican
Alabama 2nd	Republican	Republican
Alabama 3rd	Republican	Republican
Alabama 4th	Republican	Republican
Alabama 5th	Republican	Republican
Alabama 6th	Republican	Republican
Alabama 7th	Democrat	Democrat
Alaska at large	Republican	Republican
Arizona 1st	Democrat	Democrat
Arizona 2nd	Democrat	Democrat
Arizona 3rd	Democrat	Democrat
Arizona 4th	Republican	Republican
Arizona 5th	Republican	Republican
Arizona 6th	Republican	Republican
Arizona 7th	Democrat	Democrat
Arizona 8th	Republican	Republican
Arizona 9th	Democrat	Democrat
Arkansas 1st	Republican	Republican
Arkansas 2nd	Republican	Republican
Arkansas 3rd	Republican	Republican
Arkansas 4th	Republican	Republican
California 1st	Republican	Republican
California 2nd	Democrat	Democrat
California 3rd	Republican	Democrat
California 4th	Republican	Republican
California 5th	Democrat	Democrat
California 6th	Democrat	Democrat
California 7th	Democrat	Democrat
California 8th	Republican	Republican
California 9th	Democrat	Democrat
California 10th	Democrat	Democrat
California 11th	Democrat	Democrat
California 12th	Democrat	Democrat
California 13th	Democrat	Democrat
California 14th	Democrat	Democrat
California 15th	Democrat	Democrat
California 16th	Democrat	Democrat
California 17th	Democrat	Democrat
California 18th	Democrat	Democrat
California 19th	Democrat	Democrat
California 20th	Democrat	Democrat
California 21st	Republican	Democrat
California 22nd	Republican	Republican
California 23rd	Republican	Republican
California 24th	Democrat	Democrat
California 25th	Republican	Democrat
California 26th	Democrat	Democrat
California 27th	Democrat	Democrat
California 28th	Democrat	Democrat
California 29th	Democrat	Democrat
California 30th	Democrat	Democrat
California 31st	Democrat	Democrat
California 32nd	Democrat	Democrat
California 33rd	Democrat	Democrat
California 34th	Democrat	Democrat
California 35th	Democrat	Democrat
California 36th	Democrat	Democrat
California 37th	Democrat	Democrat
California 38th	Democrat	Democrat
California 39th	Democrat	Democrat
California 40th	Democrat	Democrat
California 41st	Democrat	Democrat
California 42nd	Republican	Republican
California 43rd	Democrat	Democrat
California 44th	Democrat	Democrat
California 45th	Republican	Democrat
California 46th	Democrat	Democrat
California 47th	Democrat	Democrat
California 48th	Republican	Democrat
California 49th	Democrat	Democrat
California 50th	Republican	Republican
California 51st	Democrat	Democrat
California 52nd	Democrat	Democrat
California 53rd	Democrat	Democrat
Colorado 1st	Democrat	Democrat
Colorado 2nd	Democrat	Democrat
Colorado 3rd	Republican	Republican
Colorado 4th	Republican	Republican
Colorado 5th	Republican	Republican
Colorado 6th	Democrat	Democrat
Colorado 7th	Democrat	Democrat
Connecticut 1st	Democrat	Democrat
Connecticut 2nd	Democrat	Democrat
Connecticut 3rd	Democrat	Democrat
Connecticut 4th	Democrat	Democrat
Connecticut 5th	Democrat	Democrat
Delaware at large	Democrat	Democrat
Florida 1st	Republican	Republican
Florida 2nd	Republican	Republican
Florida 3rd	Republican	Republican
Florida 4th	Republican	Republican
Florida 5th	Democrat	Democrat
Florida 6th	Republican	Republican
Florida 7th	Democrat	Democrat
Florida 8th	Republican	Republican
Florida 9th	Democrat	Democrat
Florida 10th	Democrat	Democrat
Florida 11th	Republican	Republican
Florida 12th	Republican	Republican
Florida 13th	Democrat	Democrat
Florida 14th	Democrat	Democrat
Florida 15th	Republican	Republican
Florida 16th	Republican	Republican
Florida 17th	Republican	Republican
Florida 18th	Republican	Republican
Florida 19th	Republican	Republican
Florida 20th	Democrat	Democrat
Florida 21st	Democrat	Democrat
Florida 22nd	Democrat	Democrat
Florida 23rd	Democrat	Democrat
Florida 24th	Democrat	Democrat
Florida 25th	Republican	Republican
Florida 26th	Democrat	Democrat
Florida 27th	Democrat	Democrat
Georgia 1st	Republican	Republican
Georgia 2nd	Democrat	Democrat
Georgia 3rd	Republican	Republican
Georgia 4th	Democrat	Democrat
Georgia 5th	Democrat	Democrat
Georgia 6th	Republican	Democrat
Georgia 7th	Republican	Republican
Georgia 8th	Republican	Republican
Georgia 9th	Republican	Republican
Georgia 10th	Republican	Republican
Georgia 11th	Republican	Republican
Georgia 12th	Republican	Republican
Georgia 13th	Democrat	Democrat
Georgia 14th	Republican	Republican
Hawaii 1st	Democrat	Democrat
Hawaii 2nd	Democrat	Democrat
Idaho 1st	Republican	Republican
Idaho 2nd	Republican	Republican
Illinois 1st	Democrat	Democrat
Illinois 2nd	Democrat	Democrat
Illinois 3rd	Democrat	Democrat
Illinois 4th	Democrat	Democrat
Illinois 5th	Democrat	Democrat
Illinois 6th	Democrat	Democrat
Illinois 7th	Democrat	Democrat
Illinois 8th	Democrat	Democrat
Illinois 9th	Democrat	Democrat
Illinois 10th	Democrat	Democrat
Illinois 11th	Democrat	Democrat
Illinois 12th	Republican	Republican
Illinois 13th	Republican	Republican
Illinois 14th	Republican	Democrat
Illinois 15th	Republican	Republican
Illinois 16th	Republican	Republican
Illinois 17th	Democrat	Democrat
Illinois 18th	Republican	Republican
Indiana 1st	Democrat	Democrat
Indiana 2nd	Republican	Republican
Indiana 3rd	Republican	Republican
Indiana 4th	Republican	Republican
Indiana 5th	Republican	Republican
Indiana 6th	Republican	Republican
Indiana 7th	Democrat	Democrat
Indiana 8th	Republican	Republican
Indiana 9th	Republican	Republican
Iowa 1st	Democrat	Democrat
Iowa 2nd	Democrat	Democrat
Iowa 3rd	Democrat	Democrat
Iowa 4th	Republican	Republican
Kansas 1st	Republican	Republican
Kansas 2nd	Democrat	Republican
Kansas 3rd	Democrat	Democrat
Kansas 4th	Republican	Republican
Kentucky 1st	Republican	Republican
Kentucky 2nd	Republican	Republican
Kentucky 3rd	Democrat	Democrat
Kentucky 4th	Republican	Republican
Kentucky 5th	Republican	Republican
Kentucky 6th	Republican	Republican
Louisiana 1st	Republican	Republican
Louisiana 2nd	Democrat	Democrat
Louisiana 3rd	Republican	Republican
Louisiana 4th	Republican	Republican
Louisiana 5th	Republican	Republican
Louisiana 6th	Republican	Republican
Maine 1st	Democrat	Democrat
Maine 2nd	Democrat	Democrat
Maryland 1st	Republican	Republican
Maryland 2nd	Democrat	Democrat
Maryland 3rd	Democrat	Democrat
Maryland 4th	Democrat	Democrat
Maryland 5th	Democrat	Democrat
Maryland 6th	Democrat	Democrat
Maryland 7th	Democrat	Democrat
Maryland 8th	Democrat	Democrat
Massachusetts 1st	Democrat	Democrat
Massachusetts 2nd	Democrat	Democrat
Massachusetts 3rd	Democrat	Democrat
Massachusetts 4th	Democrat	Democrat
Massachusetts 5th	Democrat	Democrat
Massachusetts 6th	Democrat	Democrat
Massachusetts 7th	Democrat	Democrat
Massachusetts 8th	Democrat	Democrat
Massachusetts 9th	Democrat	Democrat
Michigan 1st	Republican	Republican
Michigan 2nd	Republican	Republican
Michigan 3rd	Republican	Republican
Michigan 4th	Republican	Republican
Michigan 5th	Democrat	Democrat
Michigan 6th	Republican	Republican
Michigan 7th	Republican	Republican
Michigan 8th	Republican	Democrat
Michigan 9th	Democrat	Democrat
Michigan 10th	Republican	Republican
Michigan 11th	Democrat	Democrat
Michigan 12th	Democrat	Democrat
Michigan 13th	Democrat	Democrat
Michigan 14th	Democrat	Democrat
Minnesota 1st	Democrat	Republican
Minnesota 2nd	Democrat	Democrat
Minnesota 3rd	Democrat	Democrat
Minnesota 4th	Democrat	Democrat
Minnesota 5th	Democrat	Democrat
Minnesota 6th	Republican	Republican
Minnesota 7th	Democrat	Democrat
Minnesota 8th	Republican	Republican
Mississippi 1st	Republican	Republican
Mississippi 2nd	Democrat	Democrat
Mississippi 3rd	Republican	Republican
Mississippi 4th	Republican	Republican
Missouri 1st	Democrat	Democrat
Missouri 2nd	Republican	Republican
Missouri 3rd	Republican	Republican
Missouri 4th	Republican	Republican
Missouri 5th	Democrat	Democrat
Missouri 6th	Republican	Republican
Missouri 7th	Republican	Republican
Missouri 8th	Republican	Republican
Montana at large	Republican	Republican
Nebraska 1st	Republican	Republican
Nebraska 2nd	Republican	Republican
Nebraska 3rd	Republican	Republican
Nevada 1st	Democrat	Democrat
Nevada 2nd	Republican	Republican
Nevada 3rd	Democrat	Democrat
Nevada 4th	Democrat	Democrat
New Hampshire 1st	Democrat	Democrat
New Hampshire 2nd	Democrat	Democrat
New Jersey 1st	Democrat	Democrat
New Jersey 2nd	Democrat	Democrat
New Jersey 3rd	Republican	Democrat
New Jersey 4th	Republican	Republican
New Jersey 5th	Democrat	Democrat
New Jersey 6th	Democrat	Democrat
New Jersey 7th	Democrat	Democrat
New Jersey 8th	Democrat	Democrat
New Jersey 9th	Democrat	Democrat
New Jersey 10th	Democrat	Democrat
New Jersey 11th	Democrat	Democrat
New Jersey 12th	Democrat	Democrat
New Mexico 1st	Democrat	Democrat
New Mexico 2nd	Republican	Democrat
New Mexico 3rd	Democrat	Democrat
New York 1st	Republican	Republican
New York 2nd	Republican	Republican
New York 3rd	Democrat	Democrat
New York 4th	Democrat	Democrat
New York 5th	Democrat	Democrat
New York 6th	Democrat	Democrat
New York 7th	Democrat	Democrat
New York 8th	Democrat	Democrat
New York 9th	Democrat	Democrat
New York 10th	Democrat	Democrat
New York 11th	Republican	Democrat
New York 12th	Democrat	Democrat
New York 13th	Democrat	Democrat
New York 14th	Democrat	Democrat
New York 15th	Democrat	Democrat
New York 16th	Democrat	Democrat
New York 17th	Democrat	Democrat
New York 18th	Democrat	Democrat
New York 19th	Democrat	Democrat
New York 20th	Democrat	Democrat
New York 21st	Republican	Republican
New York 22nd	Democrat	Democrat
New York 23rd	Republican	Republican
New York 24th	Republican	Republican
New York 25th	Democrat	Democrat
New York 26th	Democrat	Democrat
New York 27th	Republican	Republican
North Carolina 1st	Democrat	Democrat
North Carolina 2nd	Republican	Republican
North Carolina 3rd	Republican	Republican
North Carolina 4th	Democrat	Democrat
North Carolina 5th	Republican	Republican
North Carolina 6th	Republican	Republican
North Carolina 7th	Republican	Republican
North Carolina 8th	Republican	Republican
North Carolina 9th	Republican	Republican
North Carolina 10th	Republican	Republican
North Carolina 11th	Republican	Republican
North Carolina 12th	Democrat	Democrat
North Carolina 13th	Republican	Republican
North Dakota at large	Republican	Republican
Ohio 1st	Republican	Republican
Ohio 2nd	Republican	Republican
Ohio 3rd	Democrat	Democrat
Ohio 4th	Republican	Republican
Ohio 5th	Republican	Republican
Ohio 6th	Republican	Republican
Ohio 7th	Republican	Republican
Ohio 8th	Republican	Republican
Ohio 9th	Democrat	Democrat
Ohio 10th	Republican	Republican
Ohio 11th	Democrat	Democrat
Ohio 12th	Republican	Republican
Ohio 13th	Democrat	Democrat
Ohio 14th	Republican	Republican
Ohio 15th	Republican	Republican
Ohio 16th	Republican	Republican
Oklahoma 1st	Republican	Republican
Oklahoma 2nd	Republican	Republican
Oklahoma 3rd	Republican	Republican
Oklahoma 4th	Republican	Republican
Oklahoma 5th	Republican	Democrat
Oregon 1st	Democrat	Democrat
Oregon 2nd	Republican	Republican
Oregon 3rd	Democrat	Democrat
Oregon 4th	Democrat	Democrat
Oregon 5th	Democrat	Democrat
Pennsylvania 1st	Republican	Republican
Pennsylvania 2nd	Democrat	Democrat
Pennsylvania 3rd	Republican	Democrat
Pennsylvania 4th	Republican	Democrat
Pennsylvania 5th	Democrat	Democrat
Pennsylvania 6th	Democrat	Democrat
Pennsylvania 7th	Democrat	Democrat
Pennsylvania 8th	Democrat	Democrat
Pennsylvania 9th	Republican	Republican
Pennsylvania 10th	Republican	Republican
Pennsylvania 11th	Republican	Republican
Pennsylvania 12th	Republican	Republican
Pennsylvania 13th	Democrat	Republican
Pennsylvania 14th	Republican	Republican
Pennsylvania 15th	Republican	Republican
Pennsylvania 16th	Democrat	Republican
Pennsylvania 17th	Democrat	Democrat
Pennsylvania 18th	Democrat	Democrat
Rhode Island 1st	Democrat	Democrat
Rhode Island 2nd	Democrat	Democrat
South Carolina 1st	Republican	Democrat
South Carolina 2nd	Republican	Republican
South Carolina 3rd	Republican	Republican
South Carolina 4th	Republican	Republican
South Carolina 5th	Republican	Republican
South Carolina 6th	Democrat	Democrat
South Carolina 7th	Republican	Republican
South Dakota at large	Republican	Republican
Tennessee 1st	Republican	Republican
Tennessee 2nd	Republican	Republican
Tennessee 3rd	Republican	Republican
Tennessee 4th	Republican	Republican
Tennessee 5th	Democrat	Democrat
Tennessee 6th	Republican	Republican
Tennessee 7th	Republican	Republican
Tennessee 8th	Republican	Republican
Tennessee 9th	Democrat	Democrat
Texas 1st	Republican	Republican
Texas 2nd	Republican	Republican
Texas 3rd	Republican	Republican
Texas 4th	Republican	Republican
Texas 5th	Republican	Republican
Texas 6th	Republican	Republican
Texas 7th	Republican	Democrat
Texas 8th	Republican	Republican
Texas 9th	Democrat	Democrat
Texas 10th	Republican	Republican
Texas 11th	Republican	Republican
Texas 12th	Republican	Republican
Texas 13th	Republican	Republican
Texas 14th	Republican	Republican
Texas 15th	Democrat	Democrat
Texas 16th	Democrat	Democrat
Texas 17th	Republican	Republican
Texas 18th	Democrat	Democrat
Texas 19th	Republican	Republican
Texas 20th	Democrat	Democrat
Texas 21st	Republican	Republican
Texas 22nd	Republican	Republican
Texas 23rd	Republican	Republican
Texas 24th	Republican	Republican
Texas 25th	Republican	Republican
Texas 26th	Republican	Republican
Texas 27th	Republican	Republican
Texas 28th	Democrat	Democrat
Texas 29th	Democrat	Democrat
Texas 30th	Democrat	Democrat
Texas 31st	Republican	Republican
Texas 32nd	Republican	Democrat
Texas 33rd	Democrat	Democrat
Texas 34th	Democrat	Democrat
Texas 35th	Democrat	Democrat
Texas 36th	Republican	Republican
Utah 1st	Republican	Republican
Utah 2nd	Republican	Republican
Utah 3rd	Republican	Republican
Utah 4th	Democrat	Democrat
Vermont at large	Democrat	Democrat
Virginia 1st	Republican	Republican
Virginia 2nd	Republican	Democrat
Virginia 3rd	Democrat	Democrat
Virginia 4th	Democrat	Democrat
Virginia 5th	Republican	Republican
Virginia 6th	Republican	Republican
Virginia 7th	Democrat	Democrat
Virginia 8th	Democrat	Democrat
Virginia 9th	Republican	Republican
Virginia 10th	Democrat	Democrat
Virginia 11th	Democrat	Democrat
Washington 1st	Democrat	Democrat
Washington 2nd	Democrat	Democrat
Washington 3rd	Republican	Republican
Washington 4th	Republican	Republican
Washington 5th	Republican	Republican
Washington 6th	Democrat	Democrat
Washington 7th	Democrat	Democrat
Washington 8th	Republican	Democrat
Washington 9th	Democrat	Democrat
Washington 10th	Democrat	Democrat
West Virginia 1st	Republican	Republican
West Virginia 2nd	Republican	Republican
West Virginia 3rd	Republican	Republican
Wisconsin 1st	Republican	Republican
Wisconsin 2nd	Democrat	Democrat
Wisconsin 3rd	Democrat	Democrat
Wisconsin 4th	Democrat	Democrat
Wisconsin 5th	Republican	Republican
Wisconsin 6th	Republican	Republican
Wisconsin 7th	Republican	Republican
Wisconsin 8th	Republican	Republican
Wyoming at large	Republican	Republican

That's not a bad result. Of the 435 predictions, 412 (or 94.7%) were correct.

The 23 that were wrong were:

District	Prediction	Result
California 3rd	Republican	Democrat
California 21st	Republican	Democrat
California 25th	Republican	Democrat
California 45th	Republican	Democrat
California 48th	Republican	Democrat
Georgia 6th	Republican	Democrat
Illinois 14th	Republican	Democrat
Kansas 2nd	Democrat	Republican
Michigan 8th	Republican	Democrat
Minnesota 1st	Democrat	Republican
New Jersey 3rd	Republican	Democrat
New Mexico 2nd	Republican	Democrat
New York 11th	Republican	Democrat
Oklahoma 5th	Republican	Democrat
Pennsylvania 3rd	Republican	Democrat
Pennsylvania 4th	Republican	Democrat
Pennsylvania 13th	Democrat	Republican
Pennsylvania 16th	Democrat	Republican
South Carolina 1st	Republican	Democrat
Texas 7th	Republican	Democrat
Texas 32nd	Republican	Democrat
Virginia 2nd	Republican	Democrat
Washington 8th	Republican	Democrat

Most of these are examples of seats where I backed the incumbent who then lost on a very narrow margin. At first, looking at the large number of blue results here, I assumed this was an indication of me being cautiously skeptical about the 'blue wave' narrative, but could also indicate that we gave just a little too much weight to the value of incumbency.

District	Percentage Points in excess of 50
California 21st	0.4
California 25th	4.4
California 45th	2.1
California 48th	3.6
Georgia 6th	0.5
Illinois 14th	2.5
Michigan 8th	0.6
Minnesota 1st	5.7
New Mexico 2nd	0.9
New York 11th	3.0
Oklahoma 5th	0.7
South Carolina 1st	0.7
Texas 7th	2.5
Texas 32nd	2.3
Virginia 2nd	1.1
Washington 8th	2.4

California and Minnesota, among these districts, are the only states with concerning margins of error. There were other classes of mistake, though. In California 3 the incumbent was unexpectedly re-elected with an 8.1%, contrary to an average "Likely Republican" rating among third parties and no targeted polling. The previous special election in the district may be responsible for this. In Kansas 2 and New Jersey 3, the seats were won by parties I had not predicted, though neither polled over 50.0% and the impact of Libertarian and Independent votes may have skewed the results. And then there was Pensylvania.

Most of the above I am reasonably content with as the normal variation of an electoral system, with perhaps a little need to tweak the weighting I give to incumbency. Pensylvania, however, was a significant oversight. The 16th district saw the incumbent returned with 51.6% of the vote and I can accept that. However the 4th, 13th and particularly the 3rd district are another matter.

Pennsylvania 4 was won by the Dems with 63.5% of the vote. This is in contrast with 66.1% for the Republicans in 2016 and 74.5% in 2014. That is one hefty swing, and at least in the data I was looking for there was nothing to indicate it. In fact, there was no indicator of anything--no 3rd party rating, no district-specific polling. This is typical of safe seats, as Penn 4 turned out to be, but usually safe seats are not swing seats.

Simmilar story for Penn 13 but in reverse. No recent data, but it appeared safe for the Democrats based on past voting and was won decisively by the GOP with 70.5% of the vote. In fact, this district was so safe for the Democrats historically the Republicans didn't even contest it in 2016.

Pennsylvania's 3rd district is even more extreme. Increasingly safe for the Republicans since they took posession in 2010, the Dem's didn't even contest it last election. This election though? Democrat won with 93.4% of the vote. 93.4%.

So what happened in Pensylvania that I missed was a whole bunch of redistricting that shoved safe incumbents into other seats and completely wrote off all the historical data i was relying on. That was a pretty important fact I overlooked, though I'm not sure I would have been able to get accurate data for these districts anyhow.

On the whole, though, quite a pleasing result.

The Senate

Four errors in senate predictions occured this year.

State	Prediction	Result
Arizona	Republican	Democrat
California	Democrat	Democrat
Connecticut	Democrat	Democrat
Delaware	Democrat	Democrat
Florida	Republican	Republican
Hawaii	Democrat	Democrat
Indiana	Democrat	Republican
Maine	Independent	Independent
Maryland	Democrat	Democrat
Massachusetts	Democrat	Democrat
Michigan	Democrat	Democrat
Minnesota	Democrat	Democrat
Minnesota (s)	Democrat	Democrat
Mississippi	Republican	Republican
Mississippi (s)	Republican	Republican
Missouri	Democrat	Republican
Montana	Democrat	Democrat
Nebraska	Republican	Republican
Nevada	Republican	Democrat
New Jersey	Democrat	Democrat
New Mexico	Democrat	Democrat
New York	Democrat	Democrat
North Dakota	Republican	Republican
Ohio	Democrat	Democrat
Pennsylvania	Democrat	Democrat
Rhode Island	Democrat	Democrat
Tennessee	Republican	Republican
Texas	Republican	Republican
Utah	Republican	Republican
Vermont	Independent	Independent
Virginia	Democrat	Democrat
Washington	Democrat	Democrat
West Virginia	Democrat	Democrat
Wisconsin	Democrat	Democrat
Wyoming	Republican	Republican

Mildly interestingly, these errors cancelled out so my net prediction was spot on: 22 Dems, 11 Republicans and two Independents. On a case by case basis, the 4 errors out of 35 seats is a success rate of 88.6%. Nothing exceptional, but not terrible either.

All four of these errors were seats decided at the very end of the post, based on the subjective weighting of factors under the heading "final races". This is unsurprising--the hardest seats to determine are the most likely to be called wrongly. On the upside, it does endorse the methodology used earlier in my predictions, which had a 100% predictive success rate this year. On the downside, of the five seats I called by personal judgement, I got four wrong. Florida alone came through. So that's a little dispointing.

The Gubernators

In the 36 races for governor, five predictions were incorrect. This leaves a middling success rate of 86.1%.

State	Prediction	Results
Alabama	Republican	Republican
Alaska	Republican	Republican
Arizona	Republican	Republican
Arkansas	Republican	Republican
California	Democrat	Democrat
Colorado	Democrat	Democrat
Connecticut	Democrat	Democrat
Florida	Democrat	Republican
Georgia	Republican	Republican
Hawaii	Democrat	Democrat
Idaho	Republican	Republican
Illinois	Democrat	Democrat
Iowa	Democrat	Republican
Kansas	Republican	Democrat
Maine	Democrat	Democrat
Maryland	Republican	Republican
Massachusetts	Republican	Republican
Michigan	Democrat	Democrat
Minnesota	Democrat	Democrat
Nebraska	Republican	Republican
Nevada	Republican	Democrat
New Hampshire	Republican	Republican
New Mexico	Democrat	Democrat
New York	Democrat	Democrat
Ohio	Democrat	Republican
Oklahoma	Republican	Republican
Oregon	Democrat	Democrat
Pennsylvania	Democrat	Democrat
Rhode Island	Democrat	Democrat
South Carolina	Republican	Republican
South Dakota	Republican	Republican
Tennessee	Republican	Republican
Texas	Republican	Republican
Vermont	Republican	Republican
Wisconsin	Democrat	Democrat
Wyoming	Republican	Republican

Three races tipped for the Democrats (Florida, Iowa and Ohio) went to the GOP, and two Republican predictions (Kansas and Navada) went the other way. Sustained polling success for the Dems in Florida did not translate on the one vote that actually counted. The other four predictions were based on very limited data and noted as dubious in the relevant post. These were only called because I had to bet one way or the other, and I am not at all surprised I got them wrong.