Table A.4.

Reporting rate ($\alpha$) using profile travel data.

	${\alpha }_{US}$	$\frac{1-{\alpha }_{US}}{{\alpha }_{US}}$
	5 day lag
China and Italy Travel Data
	0.0108	91.3
Only Chinese Travel Data
	0.0106	93.6
China, Italy, Spain, Germany, UK
	0.0112	88.1
	8 day lag
China and Italy Travel Data
	0.0385	25.0
Only Chinese Travel Data
	0.0330	29.3
China, Italy, Spain, Germany, UK
	0.0409	23.4

We report estimated $\alpha$ by OLS without a constant for several specifications of the model. We use $T_0$ as Feb 23rd and $T_1$ as Mar 10,13 for each lag respectively. For the versions including European data, European travel to both Iceland and the United States is considered. Hamilton OH, Allgeheny, PA; Multnomah, OR; Seminole, FL; Santa Clara, CA; and Baltimore MD counties are all excluded for zero-travel.