Pollsters traditionally look to voters registering as "independents" to answer this question. But tracking polls based on party affiliation alone have become a problem in a race between two of the most unlikeable and polarizing candidates ever recorded.
No longer does registering as a loyal Democrat or Republican imply that you are going to vote for that candidate for president. In addition, many voters who are independents are not necessarily undecided.
In trying understand the undecided voter and what may influence their voting decisions, we looked deeper than traditional polls. Each week we ask more than 1,500 voters to rank in order their candidate choices so that we can measure voter surety in their current choice, rather than applying the traditional binary "winner-take-all" approach used by most polling organizations.
This takes into account a voter's uncertainty and alternate choices, and breaks down the voter pool into statistically unique groups: Predictable supporters of Hillary Clinton and Donald Trump, and undecided voters.
By breaking down the undecided voters, we find two groups. The first "undecided" group, "rejectors," represent 17% of voters. They dislike both candidates with such passion that they would rather vote for an alternative candidate (Gary Johnson or Jill Stein) or not vote at all. They are disenfranchised and disgusted with the system based on the two main candidate choices.
The second group are voters in all party affiliations that can be swayed, and it's these "swayables" that will greatly affect the outcome in tight races such as this. Based on our analysis, 10% of voters fall into this area.
This swayable group is 34% Republican, 26% Democrat and 40% independent, proving that it is not just independent voters who are undecided. These voters cannot be labeled as "independents" or "leaners." It's a group that honestly does not know who to vote for, but will likely eventually choose one candidate.
This group cares about the economy, health care and education, with the economy far outweighing other issues. Immigration was a distant fourth among these voters' priorities, while environmental and social issues were ranked as relatively unimportant.
It is worth noting that both candidates currently seem to be focusing on issues immaterial to the very voters that could well decide the outcome of the election.
Attributes most likely to encourage swayables to vote for a presidential candidate include strong leadership skills and honesty -- not exactly what the nominees are portraying in their current advertising.
Importantly, this group has a positive impression of both candidates. They are an optimistic, "for America" group and respond differently to candidate messaging than all other groups.
In fact, the only ads airing since June 30 that swayables reported as having a negative impact on their voting intent were aired by third party candidates -- an indication that these voters do plan to vote for one of the two nominees.
For creative teams and media strategists, here's what the data shows:
Make love not war
This is a group that responds disproportionately better to positive ads from any candidate.
Campaigns seem to confuse "undecided" with "gullible." This group is not stupid, and is above average in income and education. They value honesty, credibility, and respect.
Policy, not slurs
This group is looking for reasons to vote for a candidate. Put your best foot forward by explaining your policies and beliefs, not slurs about another candidate.
The swayable 10% is the most important group of voters in the country at the moment. The campaigns that can pivot and deliver the most relevant and impactful messaging to this group will come out on top.