Table 3.

Median (interquartile range), Pearson correlation coefficient (COR), root mean square error (RMSE), and mean absolute percentage error (MAPE) for Google Flu Trends (GFT), SS0, SRR, SRS, and SSS models. Results are stratified by state population and season.

Measure			GFTa, median (interquartile range)	SS0, median (interquartile range)	SRR, median (interquartile range)	SRS, median (interquartile range)	SSS, median (interquartile range)
CORb
	Overall		0.89 (0.8-0.94)	0.56 (0.4-0.75)	0.8 (0.7-0.88)	0.8 (0.7-0.88)	0.74 (0.61-0.83)
	Population size (millions)
		0-2 (n=14)	0.83 (0.72-0.91)	0.46 (0.31-0.66)	0.74 (0.57-0.82)	0.71 (0.56-0. 8)	0.62 (0.55-0.74)
		2-5 (n=14)	0.9 (0.81-0.94)	0.58 (0.42-0.76)	0.78 (0.72-0.87)	0.8 (0.72-0.85)	0.73 (0.66-0.81)
		5-7.5 (n=10)	0.89 (0.8-0.95)	0.51 (0.36-0.64)	0.83 (0.7-0.88)	0.81 (0.73-0.88)	0.75 (0.63-0.82)
		≥7.5 (n=12)	0.93 (0.86-0.96)	0.73 (0.48-0.85)	0.88 (0.79-0.92)	0.89 (0.8-0.92)	0.86 (0.72-0.91)
	Season
		05-06	0.83 (0.71-0.88)	0.72 (0.56-0.85)	0.78 (0.68-0.86)	0.76 (0.62-0.86)	0.74 (0.66-0.86)
		06-07	0.83 (0.76-0.9)	0.75 (0.61-0.84)	0.8 (0.7-0.88)	0.8 (0.64-0.87)	0.8 (0.72-0.89)
		07-08	0.93 (0.87-0.96)	0.61 (0.47-0.77)	0.87 (0.78-0.92)	0.86 (0.78-0.9)	0.81 (0.73-0.86)
		08-09	0.81 (0.71-0.89)	0.37 (0.28-0.44)	0.7 (0.59-0.8)	0.74 (0.58-0.79)	0.57 (0.45-0.68)
		09-10	0.97 (0.94-0.98)	0.51 (0.39-0.73)	0.82 (0.75-0.89)	0.82 (0.74-0.89)	0.74 (0.63-0.85)
		10-11	0.89 (0.86-0.93)	0.47 (0.33-0.6)	0.82 (0.75-0.88)	0.81 (0.75-0.88)	0.71 (0.63-0.78)
RMSEc(1e-3)
	Overall		0.93 (0.66-1.33)	1.07 (0.68-1.84)	0.84 (0.54-1.25)	0.86 (0.55-1.27)	0.9 (0.55-1.35)
	Population size (millions)
		0-2 (n=14)	0.88 (0.63-1.29)	1.17 (0.61-1.92)	0.96 (0.55-1.47)	0.96 (0.62-1.49)	0.92 (0.58-1.44)
		2-5 (n=14)	1.02 (0.78-1.52)	1.37 (0.83-2.13)	1.04 (0.7-1.54)	1.11 (0.62-1.57)	1.11 (0.66-1.68)
		5-7.5 (n=10)	0.88 (0.67-1.48)	0.99 (0.66-1.79)	0.74 (0.49-1.07)	0.71 (0.51-1.14)	0.79 (0.55-1.24)
		≥7.5 (n=12)	0.87 (0.63-1.16)	0.91 (0.64-1.49)	0.69 (0.43-1.05)	0.67 (0.41-0.99)	0.74 (0.46-1.01)
	Season
		05-06	0.88 (0.60-1.45)	0.81 (0.49-1.47)	0.71 (0.5-1.11)	0.68 (0.49-1.13)	0.64 (0.46-1.06)
		06-07	0.82 (0.52-1.13)	0.70 (0.48-1.02)	0.59 (0.43-0.88)	0.58 (0.42-0.94)	0.56 (0.41-0.83)
		07-08	1.09 (0.70-1.55)	1.36 (0.78-1.85)	0.91 (0.54-1.27)	0.95 (0.58-1.37)	0.97 (0.6-1.42)
		08-09	1.02 (0.79-1.41)	1.21 (0.92-1.98)	0.95 (0.69-1.31)	0.93 (0.67-1.26)	1.05 (0.78-1.4)
		09-10	1.05 (0.80-1.32)	1.91 (1.28-2.44)	1.34 (0.9-1.9)	1.37 (0.92-1.92)	1.53 (1.01-1.9)
		10-11	0.73 (0.64-1.20)	1.00 (0.73-1.62)	0.73 (0.5-1.04)	0.7 (0.51-1.1)	0.86 (0.58-1.16)
MAPEd
	Overall		0.71 (0.44-1.51)	0.58 (0.38-0.8)	0.54 (0.33-0.9)	0.61 (0.34-1)	0.61 (0.35-1.02)
	Population size (millions)
		0-2 (n=14)	0.76 (0.51-1.56)	0.68 (0.48-0.86)	0.76 (0.5-1.36)	0.84 (0.56-1.44)	0.82 (0.58-1.28)
		2-5 (n=14)	0.77 (0.41-1.48)	0.63 (0.36-0.85)	0.58 (0.36-0.9)	0.64 (0.39-1)	0.68 (0.37-1.02)
		5-7.5 (n=10)	0.68 (0.4-1.41)	0.58 (0.39-0.74)	0.41 (0.31-0.75)	0.46 (0.32-0.86)	0.55 (0.34-0.92)
		≥7.5 (n=12)	0.7 (0.43-1.54)	0.4 (0.31-0.59)	0.38 (0.2-0.59)	0.37 (0.2-0.69)	0.41 (0.24-0.61)
	Season
		05-06	1.07 (0.56-2.67)	0.59 (0.39-0.8)	0.68 (0.4-0.93)	0.77 (0.41-1.12)	0.74 (0.38-1.08)
		06-07	0.88 (0.46-1.48)	0.54 (0.36-0.71)	0.51 (0.32-0.84)	0.62 (0.35-0.94)	0.58 (0.3-0.89)
		07-08	0.76 (0.5-1.57)	0.69 (0.4-0.83)	0.54 (0.38-0.78)	0.62 (0.41-0.94)	0.62 (0.38-0.81)
		08-09	0.71 (0.44-1.48)	0.57 (0.42-0.77)	0.62 (0.37-1.01)	0.66 (0.36-0.93)	0.68 (0.39-1.14)
		09-10	0.63 (0.43-1.17)	0.59 (0.36-0.85)	0.52 (0.31-1.25)	0.59 (0.31-1.38)	0.67 (0.37-1.14)
		10-11	0.61 (0.32-0.93)	0.5 (0.35-0.85)	0.38 (0.26-0.67)	0.38 (0.26-0.75)	0.43 (0.31-0.83)

^aGFT: Google Flu Trends.

^bCOR: Pearson correlation coefficient.

^cRMSE: root mean square error.

^dMAPE: mean absolute percentage error.