People say different things when talking on the phone to a person or to an automated computer over the phone when what they say to a telephone has no consequences. Especially several months away from the election, when people are not even thinking about the situation in the same way that they will come October or November.
People think and vote differently in telephone polls in May than they do in the physical voting booth after standing in line for 5 mins to 2 hours, waiting in line with other people all around them. Their thought process is completely different in the privacy of their own home, vs them being around people where they see that their actions now have consequences and they are now thinking about the decision in ways they did not before even in the quietness of their own minds.
When around people, people think differently, we engage contra-narratives and take the opposing side of our thoughts, viewpoints, and emotions and moderate our behavior to be acceptable both to ourself but also to interact in the greater group. We think with a mindset what is best for me but also what is best for the group.
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How else do you explain things like Focus Groups. When talking about physical products in a marketplace or public political figures in focus groups, a person expresses very different language, personal preferences but also public policy preferences when there is a group of individuals and 1 interviewer and yourself in a room with an interviewer.
But its also even more than that, have a group of people and an interviewer who is clear that he has no opinion and his job is to just moderate and ask questions and you get certain answers and certain styles of thinking. Yet ask the person who made the product to enter the room, or the politician, or even just someone who works for the politician and suddenly everyone's behavior changes. The language becomes either more coached and reserved or more antagonistic if there is something personal grievance between the people and the person they are talking about.
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The actual numbers for the opinion polls are useless at this stage you need to wait 4 more months before the X vs Y breakdown becomes useful. Aka 30 days before the election.
What matters now is not the actual numbers but instead the data behind the scene where people explain their feelings, their observations, and their opinions. For example how many people consider themselves undecided, and why are the reasons they are undecided. Ask them why are they feeling the way they do and then try to create models based off the feeling.
Someone who says No I am not for X is not the same thing as a person saying No I am AGAINST X, vs No FUCK NO over my dead body. All 3 examples will be counted as a no in the X for Hillary and Y for Trump but those are actually 3 very different things and those word choices and the reasons why they said those things have outcomes on things like turnout, persuading of the undecideds, but also can you say you voted for X with pride and without be considering a social outcast the next day when you go to work and you talk to someone else who will have said they voted for the other guy. Will your relationships with your greater social circle change. Will your opinions change when you realize the person in the presidency has consequences and you must thinking about this more rationally and less personally and less in an emotional way unless you can defend your emotions to your social peers.