Proportions of total and unique words are similar to those of the first debate.

Overall, the 2nd debate saw fewer words (13,485 vs 14,572, a decrease of +7.5%. As before, Obama contributed more words to the debate, with 7,031 words vs 6,454 for McCain (+8.9% more — compare this to the 7% difference seen in the first debate).

The difference in the fraction of unique words for both candidates was greater than seen in the first debate. Here, Obama edged over McCain by +3.4%.

a c b d

a :: total number of words b :: proportion of words in the debate c :: unique words in (a) d :: (c) relative to (a) bar :: proportion of (a-c):c

Stop word contribution for the 2nd debate is virtually identical to what was seen for the first debate. Actually, this is a little creepy.

In the first debate stop words accounted for 56.6% and 55.7% of words by Obama and McCain. In this debate, the numbers are 56.8% and 55.7%.

a c b d

a :: total number of words, for a given category (all, stop, non-stop) b :: (a) relative to words in the debate if category=all, otherwise relative to words by the candidate c :: number of unique words with set (a) d :: (c) relative to (a) bar :: proportion of (a-c):c

Word frequency profile is also virtually identical to the first debate. Obama continues with a slighly higher average word frequency.

a b c

a :: average word frequency b :: largest word frequency in 50% of content c :: largest word frequency in 90% of content bar :: proportion of a:b:c

In the second debate, McCain' sentences were significantly shorter than in the first debate (6.5 words vs 7.1 words), whereas for Obama sentence length remained relatively constant (7.5 vs 7.7). The first debate was a podium format and the second, a town-hall format in which some questions were asked by the audience. This more informal approach, where the candidates were engaging directly with the audience members as well as interjecting each other, likely contributed to the shorter sentences. Interestingly, McCain was more susceptible to this than Obama, whose sentence length was virtually identical to that in the more formal debate.

a b c

a :: average sentence size b :: largest sentence size for 50% of content c :: largest sentence size for 90% of content bar :: proportion of a:b:c

The difference in adverb use seen in the first debate disappeared. Instead, use of adjectives showed greater split, with their use increasing for Obama (15.8% vs 15.1%) and remaining constant with McCain (14.2%). The number of unique adjectives dropped for Obama by 2.5% (42.3% for this debate and 45.1% for the first debate) whereas McCain' unique adjectives radically increased (49.9% for this debate and 45.1% for the first debate).

McCain also showed lower noun use from the first debate (50.8% for this debate vs 53.8% for the first debate), instead increasing his verb use (28.6% for this debate vs 26.5% for the first debate).

Other than adjectives, Obama' part of speech breakdown was relatively unchanged.

a c b d

a :: total number of words for a given POS (all, noun, verb, adjective, adverb) b :: (a) relative to all words by candidate c :: unique words in (a) d :: (c) relative to (a) bar :: proportion of (a-c):c

The second debate saw quite a few differences in the frequency of parts of speech.

Although noun frequency remained relatively the same, McCain was seen repeating more verbs than Obama, a reverse of the first debate. Here, McCain's average verb frequency was 2.17 (2.06 in the first debate) and Obama's was 2.08 (2.10 in the first debate).

The use of both adjectives and adverbs saw changes. McCain decreased the repetition of adjectives from 2.22 in the first debate to 2.00 in this debate and slighly upped his adverb frequency from 2.55 to 2.62. Obama on the other hand reduced adverb repetition significantly from 2.92 to 2.53.

a b c

a :: average word frequency b :: largest word frequency in 50% of content c :: largest word frequency in 90% of content bar :: proportion of a:b:c

Compared to the first debate, the number of unique pairs relative to all pairs for a given part of speech group remained unchanged, with the exception of adverb/adjective pairs. In the first debate Obama's unique component was 83.3% and McCain's 90.4%. In this debate these values are 88.2% and 82.0% respectively. Obama repeated the same adjective/adverb pairs, whereas McCain decreased his repetition.

Given that Obama's sentences were longer for this debate than McCain's (and by a larger margin than for the first debate), it is a surprise that the total number of word pairs was not significantly lower for McCain for this debate. In fact, most of the Obama/McCain pairing ratio values increased (e.g. verb/noun increased from 80.5% to 84.6%, verb/verb from 82.2% to 91.0%, adverb/noun from 72.4% to 80.3%, adverb/verb from 70.9% to 90.2%). The largest drop was in the adjective/adjective pairings, from 78.7% in the first debate to 65.4% in this debate.

a c b d

a :: total number of pairs, for a given category (e.g. verb/noun) b :: (a) relative to all pairs c :: number of unique pairs within set (a) d :: (c) relative to (a) bar :: proportion of (a-c):c

a c   d b e

a :: total number of pairs for Barack Obama b :: relative unique pairs for Barack Obama c :: total pairs for John McCain d :: (c) relative to (a) (i.e. John McCain relative to Barack Obama) e :: relative unique pairs for John McCain bars :: values of (a), (b), (c) and (e)

Obama lowered his adverb use from 6.9% in the first debate to 5.3%. McCain, on the other hand, found a new penchant for them and his speech now had 6.1% adverb content, from 5.2%. Obama' decrease adverb use was accompanied by a higher unique adverb ratio — he not only used fewer adverbs, he repeated them less frequently.

McCain also increased his adjective use from 14.4% to 16.8% and decreased repetition of them.

McCain used fewer verbs and his unique contribution to the debate also fell. In the first debate, he contributed 39.9% unique verbs to the debate. The second time around, he only contributed 35.0%. This difference was offset with Obama's decreased unique adverb contribution, from 39.8% to 35.8%.

a d b e c f

a :: total number of words unique to a candidate, for a given POS group b :: (a) relative to all unique words to the candidate c :: (a) relative to all words d :: unique words in (a) e :: (d) relative to (a) f :: (d) relative to all unique words bar1 :: normalized ratio of (a-d):d bar2 :: absolute ratio of (a-d):d for all POS groups (first column) or POS group (other columns)

Obama delivered slightly more noun phrases than McCain on this debate (+2.6% more), a difference smaller than for the first debate, where he delivered 4% more phrases. This time, McCain had relatively more top-level phrases than Obama, at 48.4%, increasing his relative top-level noun phrase by more than 3% from the previous debate. McCain also delivered a greater fraction of unique top-level phrases, at 96.6%, relative to the first debate (92.8%).

Obama's noun phrase profile is relatively unchanged from the first debate. He did, however, deliver slightly greater fraction of unique phrases during this debate, at 84.3% (vs 82.4% for the first debae). Table 8c Legend

a c b d

a :: number of noun phrases b :: (a) relative to number of all noun phrases c :: number of unique phrases d :: (c) relative to (a) bar :: normalized ratio of (a-c):c

The difference in the richness of all phrases was smaller between the candidates for this debate. In the first debate, the difference was +8.4% in favour to Obama and during this debate this dropped to +3.7%, still in Obama's favour.

McCain's uniqueness for top-level noun phrases dropped from 0.61 in the first debate to 0.56, whereas Obama's increased slightly.

a b	a :: ratio of the number of noun phrases to number of nouns b :: ratio of the number of unique noun phrases to number of unique nouns bar :: ratio of a:b

Noun phrase frequency dropped slightly for both candidates for this debate, but the drop is minor. Word counts remained the same.

a b c

a :: average b :: 50% weighted cumulative value c :: 90% weighted cumulative value bar1 :: normalized ratio of a:b:c

Obama's Windbag Index is still higher than McCain's. The difference is the same as seen in the first debate. The index dropped slightly for both candidates, compared to the first debate, suggesting that the town hall format contributes to less repetitive and long-winded speech.

When individual index terms are compared, Obama maintains a stronger showing in the noun phrase component — all of his terms are higher than McCain' (i.e. contributing to a lower index). Obama continues to do better with verbs, but does significantly better with adverbs than in the first debate.

The main words in Obama' tag cloud remain the same: "just", "think", "important". It is interesting to see the word "nuclear" disappear from the center of the cloud. The main new word is "health", a testament to a major topic of the debate.

McCain, on the other hand, continues to use "nuclear" and in fact the relative frequency of this word is larger than before. "friends" now appears large, as do instances of "america", "american" and "americans". Presumably McCain is attempting to connect to the swing voters.

For Obama, "actually" takes center stage, displacing "absolutely" from the first debate. Obama's cloud now has a more prominent central component, suggesting that he repeated certain words with relatively higher frequency than in the first debate. Words with relatively increased frequency are "interested", "harder" and "enormous". Note that these tag clouds show words exclusive to a candidate. McCain did not use "intersted" or "harder".

McCain continues to press with "fought" and "petraeus", words consistenly avoided by Obama. McCain' use of "nervous" is interesting — certainly not a word that soothes.

The noun tag cloud shows fewer words exclusive to Obama with high relative frequencies. The sea of green in the cloud from the first debate is replaced by a more even mixture of green/blue words. In fact, words unique to each candidate were used with relatively lower frequency in this debate, when compared to the most frequently used words.

Obama says "making" and "help", whereas McCain presses for "control" and "fought". Obama' use of verbs was more varied in this debate, as indicated by fewer large words in this cloud.

The adjective tag cloud has significantly different morphology in this debate when compared to the cloud from the first debate. Plainly, there are more large words in this debate' cloud, indicating more words with relatively high frequencies.

McCain repeted adjectives like "refundable" and "excess", with Obama using "enormous", "federal", "responsible" and "interested" relatively more frequently than before.

Note the much less prominant "nuclear" in this debate — presumably people in the town forum were more interested in notions better described by "responsible", "federal", and "middle-income".

Adverbs are weakly used by both candidates. Most of them are relatively generic. However, McCain is seen using "militarily" in relative high abundance.

Once all parts of speech are mixed, both candidates showed less repetition of exclusive words, as indicated by the larger proportion of grey words.

A huge difference in Obama' noun/noun cloud, with extremely prominent (i.e. repeated) "care health", "health insurance", "children health" and "energy need". Obama' noun/noun cloud from the first debate was much flatter, showing less repetition.

McCain continues with military concepts in his adjective/noun cloud, with "nuclear power" and "national security" being very prominent. It is clear from McCain' noun/noun cloud that health care was a huge topic, because McCain shifted his speech from a stance that focused on military and threats to "care health", "american people" and "homes value".