Table 1 –

Task-Specific Training and Plotted Data Divisions

Task	Training Data (“Normal” Time Periods)	Plotted Data (Surveillance Time Periods)
Influenza Surveillance	[2011-05-22, 2011-10-02) [2013-05-19,2013-09-29) [2015-05-23, 2015-10-04) [2017-05-20, 2017-10-01)	[2011-01-01, 2018-05-01*)
Seasonal Illness Suppression	[2011-05-22, 2014-01-25†)	[2014-01-25, 2016-01-01)
COVID-19 Syndromic Surveillance Task	[2018-08-01§, 2019-06-01)	[2019-06-01, 2020-05-01)

^*Mayo Clinic transitioned from its historical EHR to the Epic EHR on this date.

^†End of moderate or greater ILI activity within the State of Minnesota for 2013-14 influenza season.

^§Three months after EHR migration began, to allow for clinical workflow changes to be solidified and reduce data volatility.