Table 2. Readability and quality data for three different search terms on popular search engines.

where 'n' is the number of webpages analysed

Search Term	Search Engine	Flesch–Kincaid Grade Level Mean (95% CI) for n=20	Flesch Reading Ease Score Mean (95% CI)  for n=20	Gunning Fog Index Mean (95% CI)  for n=20	SMOG Index Mean (95% CI)  for n=20	Discern scores Mean (95% CI)  for n=20
CT Risk	Google	7.37 (4.44 - 10.29)	55.24 (34.18 - 76.30)	8.61 (4.67 - 12.54)	6.85 (4.70 - 8.99)	4.35 (2.63 - 6.07)
	Yahoo	7.87 (5.37 - 10.36)	52.60 (33.32 - 71.87)	9.25 (6.10 - 12.39)	7.20 (5.14 - 9.26)	3.85 (1.36 - 6.34)
	Bing	8.10 (4.40 - 11.79)	50.55 (25.27 - 75.82)	9.14 (5.12 - 13.16)	7.29 (4.81 - 9.76)	3.85 (1.62 - 6.08)
	Unique Websites n=40	7.59 (4.33 - 10.85)	54.09 (31.55 - 76.62)	8.86 (4.78 - 12.94)	7.04 (4.74 - 9.33)	3.88 (1.60 - 6.15)
CT Harm	Google	7.19 (4.03 - 10.34)	58.29 (37.22 - 79.36)	8.86 (4.91 - 12.81)	7.02 (4.68 - 9.36)	4.45 (2.83 - 6.07)
	Yahoo	7.27 (4.15 - 10.38)	57.21 (33.80 - 80.62)	9.03 (5.61 - 12.44)	6.94 (4.96 - 8.92)	3.40 (0.90 - 5.90)
	Bing	7.17 (3.89 - 10.45)	57.97 (32.41 - 83.52)	9.01 (5.46 - 12.55)	6.78 (4.64 - 8.92)	3.45 (0.95 - 5.95)
	Unique Websites n=37	7.18 (3.99 - 10.37)	57.97 (35.58 - 80.36)	8.83 (5.05 - 12.62)	6.91 (4.68 - 9.13)	3.83 (1.40 - 6.25)
Dangers of a CT Scan	Google	7.33 (3.37 - 11.28)	56.17 (29.55 - 82.79)	8.64 (3.78 - 13.50)	6.90 (4.15 - 9.65)	4.10 (2.10 - 6.10)
	Yahoo	7.43 (4.30 - 10.56)	55.24 (31.97 - 78.51)	8.50 (5.52 - 11.47)	6.89 (5.05 - 8.73)	4.00 (1.71 - 6.29)
	Bing	7.11 (4.40 - 9.81)	57.94 (37.67 - 78.21)	8.15 (5.76 - 10.54)	6.77 (5.02 - 8.51)	4.20 (2.45 - 5.95)
	Unique Websites n=40	7.30 (3.82 - 10.78)	56.62 (31.82 - 81.42)	8.49 (4.60 - 12.38)	6.88 (4.70 - 9.07)	3.92 (1.78 - 6.05)
Total	Total [n=180 websites (unique websites n=77)]	7.29 (3.76 - 10.81)	56.38 (31.32 - 81.43)	8.51 (4.57 - 12.46)	6.84 (4.61 - 9.06)	3.58 (1.20 - 5.97)