Table 1.

Sub-group analysis for basic reproduction number ($R_0$ ) based on a random effects model.

Characteristics	Number of Reporting	R0 (95% CI)	p Value
			Heterogeneity
Method considered	(n = 161)
Exponential growth model	20	3.06 (2.32–4.03)	<0.001
Moment generating function of the Lotka–Euler equation	6	2.47 (2.13–2.86)	<0.001
Compartmental model	87	2.99 (2.67–3.35)	<0.001
Logistic model	4	2.60 (1.94–3.48)	<0.001
Others	44	2.24 (1.87–2.69)	<0.001
Duration of data	(n = 127)
≤2 weeks	15	2.74 (2.26–3.31)	<0.001
2 weeks–1 month	28	2.70 (2.11–3.46)	<0.001
1–2 months	53	2.45 (2.06–2.91)	<0.001
>2 months	31	2.86 (2.47–3.32)	<0.001
Last month of data	(n = 128)
January	25	3.34 (2.89–3.87)	<0.001
February	14	2.23 (1.40–3.56)	<0.001
March	30	2.18 (1.73–2.76)	<0.001
April	13	2.72 (1.99–3.71)	<0.001
May	12	2.69 (2.40–3.01)	<0.001
June	30	2.80 (2.31–3.39)	<0.001
July	4	2.60 (1.94–3.48)	<0.001
Month of publication	(n = 130)
January	8	3.87 (2.97–5.03)	<0.001
February	11	2.90 (1.92–4.37)	<0.001
March	6	3.18 (2.28–4.45)	<0.001
April	11	3.37 (1.93–5.89)	<0.001
May	26	2.22 (1.74–2.85)	<0.001
June	11	2.12 (1.58–2.86)	<0.001
July	40	2.83 (2.43–3.28)	<0.001
August	6	2.04 (1.70–2.45)	<0.001
September	8	2.27 (2.12–2.43)	<0.001
Country	(n = 130)
China	43	3.02 (2.55–3.59)	<0.001
Other	49	2.24 (1.87–2.68)	<0.001
USA	5	4.09 (2.60–6.43)	<0.001
Italy	8	2.69 (2.08–3.48)	<0.001
India	7	1.91 (1.56–2.33)	<0.001
France	5	2.68 (2.18–3.29)	<0.001
UK	4	3.43 (1.99–5.91)	<0.001
Spain	5	3.02 (2.22–4.09)	<0.001
Germany	3	3.18 (1.99–5.08)	<0.001
Continent	(n = 126)
Asia	66	2.54 (2.18–2.96)	<0.001
Europe	50	2.78 (2.46–3.15)	<0.001
North America	8	2.74 (1.62–4.64)	0.002
Africa	2	1.94 (1.27–2.98)	<0.001
Type of central estimate	(n = 130)
Mean	34	2.99 (2.43–3.68)	<0.001
Median	13	2.39 (1.91–2.98)	<0.001
Other	83	2.58 (2.28–2.92)	<0.001
Location in China	(n = 43)
Wuhan	8	3.40 (2.61–4.44)	<0.001
Hubei including Wuhan	2	3.39 (2.48–4.64)	<0.001
Outside Hubei in China	6	1.50 (0.76–2.96)	<0.001
China overall	27	3.39 (2.84–4.04)	<0.001