Table 3. Top nodes by eigenvector centrality.

The table lists the most central concepts of each sentiment network ranked by eigenvector centrality score (greater than 2 standard deviations from the mean).

Eigenvector centrality
Positive sentiment network		Negative sentiment network		Neutral sentiment network
Mean = 0.0626		Mean = 0.0318		Mean = 0.0975
Std Dev = 0.0936		Std Dev = 0.06		Std Dev = 0.11
parents	1	vaccines	1	SB 277	1
vaccines	0.8209	children	0.6188	vaccines	0.4304
measles	0.7458	thimerosal	0.5248	anti-vaccination	0.4177
vaccination	0.6373	CDC	0.5054	parents	0.3863
children	0.5382	vaccine industry	0.4898	children	0.3830
SB 277	0.4207	mercury	0.4440	pertussis vaccine	0.3540
autism	0.4025	autism	0.3894	home-school	0.3209
community	0.3937	flu shots	0.3367	education	0.3206
religious groups	0.3905	mainstream media	0.3342
anti-vaccination	0.3802	doctors	0.2862
vaccine-autism link	0.3608	SB 277	0.2659
herd immunity	0.3058	vaccine ingredients	0.2632
vaccine refusal	0.3024	mandatory vaccines	0.2457
vaccination exemption	0.3013	pharmaceutical companies	0.2400
personal belief exemption	0.2909	vaccine-autism link	0.2041
disease	0.2829	toxic chemical ingredients	0.1999
measles vaccine	0.2706	aluminum	0.1889
schools	0.2685	vaccination	0.1853
HPV vaccine	0.2674	monosodium glutamate	0.1811
vaccine delay	0.2603	hepatitis B vaccine	0.1793
meningococcal disease	0.2551	vaccine-injured children	0.1763
		vaccine safety	0.1721
		evidence	0.1655
		informed consent	0.1643
		intelligent questions	0.1612
		formaldehyde	0.1609
		pregnant women	0.1598
		pandemic H1N1 swine flu vaccine	0.1595
		Big Pharma	0.1591
		vaccines are safe	0.1565
		quackery	0.1552
		vaccine damage	0.1547
		SV40	0.1545
		science	0.1531