The following data is the result of an analysis of John McCain and Barack Obama's campaign speeches given from February 10, 2007 until August 19, 2008, and of the Republican and Democratic National Conventions.


In order to examine how frequently both presidential campaigns employ certain words and themes over a given period of time, we distinguished between four distinct phases:

Phase 1: February - August 2007
Phase 2: September 2007 - February 2008
Phase 3: March - May 2008
Phase 4: June - August 2008

1. Change

The first chart shows the how often Barack Obama and John McCain use the lemma (headword) change:

From February - August 2007 (Phase 1), Obama uses the lemma change about eight times more than John McCain. In a decisive phase of the Democratic and Republican primaries (September 2007-February 2008, phase 2), both rapidly increase their usage. From March - May 2008, their usage drops again (Obama: 28.8 to 21.1, McCain 17.0 to 11 words/10.000 words) before rising again in the summer (June - August 2008, phase 4).

Although Barack Obama still uses the lemma change more than John McCain, it is striking that the frequency gap between the two campaigns narrows over time; a clear indication that John McCain has begun to adopt the theme on a semantic level.

2. Reform

The second chart of Obama and McCain's usage of the lemma reform illustrates a different development:

Starting in September 2007 (Phase 2), John McCain has employed the theme of reform on a much higher level than Barack Obama; about four times as much (McCain: 18.4, Obama 3.8 words/10.000 words).

Despite his fewer usage of the lemma from March to May 2008, McCain returned to the theme in the summer, while Barack Obama remained on a relatively consistent level throughout the campaign.

3. War

Unsurprisingly, both presidential candidates frequently employed the lemma war in their campaigns, as is indicated by the chart below:

With a total average 31.3 words/10.000 words for Obama and 29.7/10.000 words for McCain for all of their campaign speeches, both candidates show a very high frequency of the lemma war.

Although Obama overtakes McCain from September 2007 to February 2008 (phase 2) and March to May 2008 (phase 3) in his references to war, both candidates' frequency declines toward the summer 2008.

4. Energy

One explanation for the drop in frequency of the lemma war is the emergence a new and urgent issue that is brought about by sharp rise of U.S. gas prices: energy.

As the chart above illustrates, both candidates have relatively low frequency rates for the lemma energy before the summer 2008, when their frequency rates triple in the case of Obama (from 8.47 to 24.74/10.000 words) and even quintuple in the case of McCain (from 6.39 to 35.88/10.000 words).

It is especially noteworthy how John McCain now discovers this topic and overtakes Obama frequency rate by a significant margin.

5. Republican and Democratic National Conventions

The analysis of Obama and McCain's campaign speeches is corroborated by an evaluation of the Republican and Democratic National Conventions in August 2008.

As the columns show, the Democratic speakers more often than their Republican counterparts used the lemmas change, energy and war. The Republicans, on the other hand, had a higher frequency of the lemma reform, similar to John McCain's campaign speeches.

What is noteworthy, however, is the fact that the Democratic convention more than twice as much employed the lemma change, trying to present themselves as the true party of change (while John McCain attempts to narrow Obama's lead with respect his usage of change in his campaign speeches).

Along these lines, the Democrats also maintain a higher frequency rate of the lemmas war and energy, although John McCain has overtaken Barack Obama in the frequency of these issues in direct comparison (see analysis of campaign speeches above).

6. Conclusions

While Barack Obama from the very beginning carefully crafted his image as an agent of change, John McCain presented himself as a reformer. McCain's rhetoric, however, shows a more frequent usage of the lemma change over the summer 2008, attempting to close the gap in frequency with Obama.

The relatively high frequency rate of the lemma war experienced a sharp decrease for both candidates with the beginning of summer. This coincides with a dramatic rise of the frequency for the lemma energy, most likely caused by the increase of U.S. gas prices in these months. In other words, semantically, energy can be considered one of the issues that replace the theme of war in frequency in the candidate's campaign speeches.

The frequency rates of the analyzed lemmas in the McCain and Obama's campaign speeches largely replicate themselves during both party's national conventions. In contrast to a direct comparison between the two candidates rhetoric over time, however, the Democrats maintain a substantial lead in the employment of change and a minor ones for the usage of the lemmas war and energy during their convention.

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