Are Johnson and Stein helping or hurting Clinton and Trump - an Analysis [View all]

Perhaps you have wondered how the inclusion of the Green and Libertarian Party candidates, Gary Johnson and Jill Stein, is affecting the race between Hillary Clinton and Donald Trump. It is something I have wondered about for some time so I finally decided to try analyze that situation. This is this methodology I devised.

With two 3rd party candidates siphoning off votes from the both of the two major party candidates it is difficult to determine whether, for example, Johnson helping or hurting Hillary? Or whether Johnson is helping or hurting Trump? However, we can take some examples of what I will call “paired polls” of the national race and those in some of the states, make some common sense assumptions, and come to some reasonable conclusions about who is hurting or helping who.

When I talk about “paired polls” I am referring to situations where polling organizations ask their sample populations their preferences in both the two person race and the four person race.

Example 1:

The following are the results of a set of paired polls for the State of Pennsylvania conducted by Suffolk University between 7/25 and 7/27:

Clinton 44, Trump 44, Tie

Clinton 43, Trump 39, Johnson 5, Stein 1 Clinton +4

Notice that when the 3rd party candidates are added, Clinton's percentage drops by 1% (44% - 43%) and Trump’s percentage drops by 5% (44% - 39%). Already we can see that Hillary does better against Trump in the 4 person race, but how do we figure out which of the third party candidates is helping her the most? Now let's make a common sense assumption - that Stein is siphoning off votes only from Clinton in a 4 person race. (Rational; It seems highly unlikely people who vote for Stein in a 4 person would vote for Trump in a 2 person race. I could see Stein voters sitting out a two person race or writing in a candidate, but I can’t see them voting for Trump. This might not be a perfect assumption, but it good enough for our purposes.) Note the total percentage of voters in each of the two types of races both add up to 88%. So it doesn’t look like any voters are moving to the undecided or voting other columns when moving from the 4 person race to the 2 person race so this factor can be ignored.

Proceeding with our assumption, we add Stine's voters to Hillary's to reduce the 4 person race to a imaginary three person race:

Clinton 43, Trump 39, Johnson 5, Stein 1 Clinton +4 (4 person race)

To: Clinton 44, Trump 39, Johnson 5 Clinton +5 (3 person race)

Now let's compare the three person race (above) the two person race (Clinton and Trump):

Clinton 44, Trump 44, Tie

Clinton 44, Trump 39, Johnson 5 Clinton +5

When Johnson is included, Clinton's total decreases none at all (44% to 44%) while Trump's total decreases by 5% (44% to 39%)

Conclusions: In this set of paired polls, Johnson’s presence in the race hurts only Trump when we assume that Stein hurts only Clinton with her candidacy. We can also see that Johnson hurts Trump far more than Stein hurts Clinton.

You can use this this basic analysis technique on any of the paired polls you can find on line. However, this is basic example and some paired polls can be more difficult analyze and additional assumptions sometimes need to be made. Examples of the analysis of other paired polls along with an overall conclusion can be found in the original article - follow this link:

Are Johnson and Stein helping or hurting Clinton and Trump - an Analysis