In their book “The Timeline of Presidential Elections,” Robert Erikson and Christopher Wlezien show that voter preferences tend to be very stable in the fall,
but that campaign observers -- the authors analyze people betting money in online political prediction markets -- tend to assume those preferences are far more volatile."
https://www.bloomberg.com/view/articles/2012-09-26/why-undecided-voters-won-t-be-deciding-this-election
The argument then is that the block of "undecided voters" is really more about hope by the political operatives, than reality.
"...the candidate that is most engaging and least offensive is the candidate who wins this essential bloc—and therefore the election.
They’ll tell you, and tell themselves, that they’re voting for the candidate with the best ideas.
But they’re really voting for the one who they believe is most “on their side.”
http://time.com/4424053/frank-luntz-the-myth-of-the-undecided-voter/
In the end, subtlety will sway more undecided voters than the sledgehammer.
"The 28 exceptions to the Incumbent Rule help support the theory on why this happens.
Many challengers who did not get a majority of undecideds in the election were recent or current holders of an office equal to the one they were seeking.
Voters were equally or more familiar with the challenger's past performance in a similar office, so the challenger assumes incumbent."
http://www.lib.niu.edu/1989/ii890428.html
This analyis tries to promote the theory that undecideds tend to vote for the challenger to an incumbent.
This approach is an attempt to use mathematical precision - but as is very obvious,
there are really too many exceptions using this approach to find a generalized and simple rule.
All analysis tends to agree that undecided voters tend to be those that are the least interested in the election
The actual (apparent) interest in any particular candidate as in the huge crowds that Trump often pulls, is really not a good indicator of how these people will vote - if they bother to vote at all.
It is not really the issues that he claims he can solve - but the opportunity to vent anger at a system that has passed them by,
a sense of entitlement that has no laudable arguments except what they perceive as their traditional birthright.
Where Trump falls very short is that while he does present himself as a champion for this large neglected block of blue collar workers (as did Bernie Saunders),
he offers no real remedy at all - except 'trust me'.
This combination of (often vulgar) pandering showmanship - with no uncomfortable and complex narratives - is really entertainment for the undecideds.
not clarity.