High voter turnout?

[millwx]

Just curious about some UNBIASED opinions on how a potentially high voter turnout could impact the election results this year.  I'm of two minds myself...

1) Reps tend to be more motivated and turn out more, therefore, high voter turnout could be a reflection of a charged up Rep Party... meaning the Reps do better.

2) By the same token, since Reps turn out more normally, that leaves a greater number of untapped Dems... so, high voter turnout could mean more Dems show up, meaning they do better.

I raise this issue because some analysts think this election year will see high voter turnout (I'm skeptical, as many voters don't seem enamored with either candidate, but let's go with this assumption...), and it seems to me that these "extra" voters may well get missed by most "Likely Voter" screens.  This could yield a systematic bias in all LV polls.  But... in what direction???

[millwx]

This will NOT cause a systematic skew in the better public opinion polls.

To use the Gallup model for example, they don't simple take a stab what they think turnout will be - they take a long series of questions and assign each voter a "score" based on many things such as past voting behavior but also current they persons current level of interest, level of attention, motivation, strength of support, etc...

My concern is how much of a weight past voting behavior gets.  It seems to me that the very fact that it is an included factor will create this systematic bias.  The bias may well be largely mitigated by these better polling firms by weighting in other factors as well (level of interest, etc), but nonetheless, it seems like this turnout - due to the past voting screen - remains a wildcard.  Now, maybe, by comparing to past elections and making adjustments in that regard those better polling firms can FURTHER compensate (maybe use a slightly lower "score" to qualify someone as "likely"?)... as you point out.  So...

You've identified some firms whose polling results would be not impacted (or at least less impacted) by this voter turnout complexity.....  Which polling firms do you think have either a worse likely voter screen OR lean too heavily on past voting behavior (so, they could get burned by turnout)?  Thanks!