Wow! You have just blown my mind! And to think that thousands of psychologists, sociologists and market researchers couldn’t figure that out for decades. What were they thinking?
The math is the easy part here. All the rest is hard.
How can you reach as many people as possible? How can you make sure that you reach a random sample of people? If you give up on that because it’s pretty hopeless, how can you make sure that the characteristics you pick to build your sample (for example age, gender, race, etc.) actually matter, are correctly chosen and that you have the right information about how your sample should look when it comes to those characteristics? (This problem can be rephrased as: How do you make sure your sample is representative? It is, however, important to unpack the complexity involved in that.) How do you know that those who tell you they will go vote will actually vote?
That’s not a complete list of problems. As you can see there are more than enough opportunities for error here.
Now, given Gallup’s poor performance compared to other polls I do not want to excuse them. They screwed up, there is not question about that. I do not think, however, that there is any need to make up conspiracy theories.
I wonder if it actually works in that political direction. If I knew my preferred candidate was down perhaps I'd be more determined to get down the polling station. Conversely if he was clearly ahead, perhaps I'd be more inclined to skip voting. ( I'm talking theoretically, I always vote, it's the law here)
My understanding is that as a non-incumbent campaign, you ideally want voters to believe that your candidate is behind but gaining and that the result will be close.
"Our final estimate of registered voters was an unallocated 49% for Obama, 46% for Romney. The transition to likely voters moved that to the unallocated 49% Romney, 48% Obama."
Ouch. So their "transition to likely voters" estimation is just completely off.
