Since there is a range in the number of polls per state (a low of one and a high of 15) there was some variation in the number of polls that were considered recent or dated. The following rules have been adopted to deal with these differences:
- If there has only been one poll conducted in a state, that is all the information on that state. Those poll numbers are left as they are, neither discounted nor weighted.
- If a state has had two or three polls since Super Tuesday the more recent one was given extra weight while the dated one (or two were) was discounted.
- Any state that had four polls over this period had the two most recent polls weighted while the earliest two polls were discounted.
- Finally, in all the states that had five or more polls the three most recent polls were given added significance while all the other polls were discounted to account for decay over time.
To the maps!
In comparing the weighted Obama map to the unweighted one (see link under Recent Posts at the bottom), several things are clear. There is a lot less light blue and purple and much more brown. Many of the states that were leaning toward Obama or were toss ups favoring him moved into the McCain column. Whereas last week's maps showed an even split in the number of toss up states between Obama and McCain, this map has 11 of the 15 total toss ups favoring McCain. As a result, the race between the two in the electoral college has gone from a virtual tie to an 80 electoral vote advantage for McCain (309 to 229) with 174 toss up electoral votes. Among the states where the candidates were either strongly ahead or held a solid lead, Obama led 192 electoral votes to 172. McCain, then, took 137 or those 174 toss up electoral votes.
And Clinton? Her map and the resulting electoral college projections are nearly identical to the unweighted map. There are changes in the map on the margins, but the electoral vote tally is exactly the same (304 to 234 for McCain). That indicates that she has managed to maintain a certain standing against McCain, but that Obama's recent troubles have not changed the perceptions of those polled in regard to her standing against the Arizona senator.
And what of the difference each candidate makes in the various states? Here too, the maps are largely similar. The states shaded on each candidate's map are the same with the weighted data as they were before the transformations to the data were made. The difference is the magnitude of the differences. The Obama map is much lighter now. There are many more yellows and greens now than purples and blues. When the more recent polls are given greater value, the impact Obama had by being the head of the ticket against McCain is erode in relation to Clinton. In other words, the McCain margins between the two are narrower in many of the states. Obama's slide then has pulled him back down to earth; to the point that there really isn't a "dime's worth of difference" between Clinton and himself.
So, now I have appeased the Clinton supporters on their methodological concerns, but probably have both camps agitated with me over how the maps now look. I have argued before that the cloudiness over who the Democratic nominee will be has suppressed some of the support the party's nominee should get given the state of the typical general election indicators (presidential approval and economy). In that regard then, this is something of a worst-case scenario for the Democrats. It does underscore how the divisiveness of the post-Texas/Ohio race has hurt them and makes that much more understandable the calls from the party's elite to decide this thing earlier rather than later.
Related: Obama's Slide Revisited
The Electoral College Maps (4/30/08)
***Please see links to past maps in the right side bar***
The State of the Race: Counting Delegates in the North Carolina Primary
The State of the Race: Counting Delegates in the Indiana Primary