This is hardly a new observation, but it's not recognized nearly well enough:
As someone who spends quite a lot of time working statistics, I'd like to point out that a move from a polling result outside to one inside a margin of error is not, itself, necessarily a statistically significant move. And even the apparently significant 8-point swing over the week could represent anything from a wiggle to a big Obama drop.
The MOE on these Gallup tracking polls is +/- 3. That means >6 point separation is required for statistical significance at the 95% confidence level.
Yet, it also means that at that confidence level, the results of each finding in any poll are subject to a fluctuation of +/- 3% entirely as a result of sampling error.
So, Obama 49, Clinton 42 +/3 could be expressed as a "confidence interval" as Obama 46-52, Clinton 39-45. That entirely encompasses the results from the next day's rolling sample, O: 47 / C: 44.
Even though one day's results are "statistically significant" and the other day's are not, the difference between the two days is another matter. These poll results alone actually prove nothing about movement from day 1 to day 2 - that "movement" could be fluctuation around the true mean based on sampling error.
On the other hand, the movement from 51/40 to 47/44 across several days is more convincing. 51 +/- 3 is 48-54; 47 falls outside that range. Yet even there, not by so very much.
There are ways to test the level of confidence with which we can say 51/40 to 47/44 represents a real movement that require more data than Gallup publicly (at least to my knowledge) releases, but we can look at these MOEs and say yes, there likely is some real movement. Yet how much? Well, with full raw data from Gallup we could create a maximum likelihood model describing the most probable degree of movement. We can't say for sure that there has been an 8 point swing (O -4, C +4). That's merely one possibility in a probability cloud, that probably ranges from something like a "true" but rather trivial 2 point swing (O -1, C +1), to a much more impressive 14 point swing (O -7, C +7).
And in response to what? Well, just as the actual degree of separation between the two candidates has sampling error, and the meaning of a "movement" has sampling error, the timing of any movement has even more potential for statistical error. Looking strictly before the debate, the movement is all reasonably within the MOE. Looking strictly after the debate, the movement is all reasonably within the MOE. It's only combining the two that we have what appears to be significant movement. A cumulative effect of recent developments? Maybe.
Finally, we have to bear in mind that comparing two samples based on their margin of error would normally involve an assumption that the two samples are independent. Unless you're comparing across > 3 days, they're not independent (two consecutive rolling samples share 2/3 of their data). So it takes the Apr 14 - 17 separation before the statistics are simplified by meeting the assumption of two independent samples, rather than sharing some of the same error variance.
In other words, while we can look at these results over the last week and say yeah, this hasn't been Obama's best week of the campaign, what I think people really want to know is: a wiggle or a real drop?
Based on what Gallup releases... we don't actually have a basis to draw a conclusion. Even if we all had the statistical background to deal with all these issues, we lack the raw data to be able to run all the stats. We can just make rough guesses based on means and MOEs. This could be either a wiggle, or a plummet, or something in between.
Overall, honestly we spend way too much time dwelling on changes in horse race polls, especially just one poll, without really knowing what we're looking at.
Congrats, Chris. Even when (say, for the last 11 months or so!) I've been too overwhelmed by competing demands to delve in and participate, I always, always stop by each day to read and think about your insightful analysis. And so now I'll have another must-read daily stop on my morning before-I-really-get-down-to-the-work-I-g
et-paid-for procrastination period at the start of the day -laugh. Good luck.
I can't believe I know this, but... on ratings pages for individual comments, the names of raters link to a page http://www.mydd.com/user/uid:# where # is the UID number. If a user has ever rated a post you can find their UID this way without being an administator, using a circuitous route leading through their user page.
Like I say, if you care. I rather like the fact that this information is harder to find now than it used to be (prior to the last major site upgrade). Reduces the temptation to judge comments by seniority instead of content.
Sorry, I was rushing, and should have been clearer.
No copy is available online yet, to my knowledge. The closest thing is the DC FAIR Act, which HR 5388 was modeled after.
To be more precise about the current bill, I understand from personal correspondence that 5388 also included a non-severability provision - at least as of a few days ago, before committee markup. I was curious about this and had someone I could ask. Norton has shown a sensitivity to this issue in the past (e.g., here).
Still, we'll clearly need to see the text that actually comes to the floor.
Yes, those quotes do need support. I realize that there is a controversy regarding the constitutionality of the bill. But I'm not aware of any systematic analysis that would support the idea that "most legal experts" believe the law is unconstitutional. In fact, the opinion of "most legal experts" appears to depend on the particular journalist, pundit, politician, or legal expert writing the story. (I've also seen undocumented claims that "most legal experts" believe this is just fine under the DC clause and the inherent powers of Congress. Since IANAL, I'll leave it to others to sort that out.)
Re: looking forward vs. backwards - I don't think it's clear that they're equally constitutional. Projected priority values aren't based on an actual enumeration. But, again, I won't go any further down the road of offering unqualified opinions on constitutional law - smile.
Re: your other points, I agree with the analysis by bschak suggesting that repeated resizing of Congress for partisan advantage is highly unlikely, with or without this precedent. Not sure how much more there is to say that he, I, or you haven't.
One could imagine a compromise making the legislation effective as of the 2010 reapportionment. That would address your concerns about mid-decade gamesmanship. Of course, that could be a poison pill, since it would eliminate the incentive for Utah Republicans to support it (they seem to think they're getting an extra seat in 2010 regardless). And I suppose it's a pretty a pointless hypothetical, anyway, since I don't know of anyone in Congress who has suggested such a thing.
You appear to be attributing arguments to proponents for this bill that I haven't heard them making. No one, to my knowledge, has been arguing that the number should be increased to 437 rather than 436 because DC would be "cutting in line" in front of Utah. It's been pretty clear from the outset that the argument for Utah is strictly about political balance.
If your point is that the bill creates a legal just-so story in order to balance a Dem seat with a Republican seat, while not openly and arbitrarily cherry-picking a single state - of course! This is a political trick that could only have worked between 2001 and 2010, after one set of priority values were released that happened to put a very red state in position 436, and before the next one (who knows, Massachusetts may be 437 next time!)
But crass political motivations don't change the fact that naming Utah in the statute and expanding the numbers while only naming DC... but knowing (wink, wink, nudge, nudge) where the other seat will go... are very different precedents. Even if they begin with the same motivation and the same result, only one of these precedents sustains the principle that seats are only apportioned amongst states based on population, after giving each state its guaranteed 1 slot.
Sometimes the difference between two routes toward the same result does matter.
You're right, of course, that Congress could begin repeatedly changing its own size to the advantage of whichever party is currently in control. But they have always had that ability. The question is, does this bill create a new political precedent that increases the acceptability of "playing the numbers" like that in the future?
If you are right that this is about "cutting in line," then we do indeed have a problem - there is no limit to how many new seats have to be created to compensate. But if it's about political balance - not adding a new likely Dem seat without also adding a new likely Repub seat and vice-versa - then it's singularly unamenable to partisan mischief. Neither party can gain a clear advantage that way.
That's how Eleanor Holmes Norton sees it. She also sees the Alaska/Hawaii precedent differently than you do - as precedent, amongst others, showing that seats are never added to Congress except in partisan political balance.
No, you're missing the importance of the way this law was written. It only specifically mentions DC. The other added seat goes to Utah because it was next in line if there had been 436 seats in Congress to apportion after the 2000 census.
Turns out, in fact, that if there were 437 seats, Utah would have gotten one (436), and the next would have gone to New York (437). Add more seats? You get Texas (438), then Michigan (439). The Priority Values that determine these things are worked out through a mathematical formula based strictly on population count and the number of representatives each state has already.
The fact that Utah was #436 on the list was very convenient in terms of getting Republican support for this bill. But there is absolutely no precedent being set here that would allow Congress to arbitrarily start handing out new seats to red states.
How will Davis' measure affect DC's electoral votes? How will it effect those of Utah? Will it be the case that DC's electoral votes stay at 3 -- which would seem to make sense -- while Utah's increase by one, thus giving the GOP an extra electoral vote?
In a word, yes. The constitution is very specific in how it allocates electoral votes to DC - nothing Congress does will change that (short of amending the constitution of course):
The District constituting the seat of Government of the United States shall appoint in such manner as the Congress may direct: A number of electors of President and Vice President equal to the whole number of Senators and Representatives in Congress to which the District would be entitled if it were a State, but in no event more than the least populous State
Utah, on the other hand, will get the extra electoral vote for having a larger Congressional delegation.
Honestly, this is a sacrifice I'm willing to make in order to take a step away from the travesty of having a major US city with no congressional representation. And remember that, while DC's congressional rep under this scheme is permanently locked in to DC, there is no guarantee that Utah keeps theirs indefinitely. If you call DC's rep the 436th, then the new 437th rep. goes wherever the census says it should, changing every 10 years, just like all the others. In fact, Utah isn't mentioned in the proposed new law at all. The law specifies that whichever state was entitled to the next seat, according to the last census, gets it until the next census. That's Utah, which experienced explosive population growth in the 1990s.
Agreed. Things like ten word taglines are only as powerful as the "cognitive models" or "schemata" they evoke (in other words, the whole cluster of associations that come to mind when you hear the phrase). Those models get built up over a period of time - not overnight with a pithy phrase. And, to add to your example, you want it to work both ways - people hear "broader prosperity" and think health care; and people hear Dems talking about health care and think "ah, yes, broader prosperity."
This doesn't mean that it's worthless to come up with good succinct ways to describe progressive principles, because that can provide a kind of goal for us to all work toward. Then we go back and forth between identifying discrete characteristics we'd like to be identified with and fleshing them out in the public imagination (through well-publicized actions). Sometimes you can piggy-back on well-established models and claim ownership of them - like "good government," which already brings to mind a lot of associations that the Democrats can fairly easily hitch their wagon to without much modification.
But this kind of stuff is definitely not an end to itself.