Table 1.

Comparison of CDR-based tracking as opposed to smartphone-based tracking of mass population movement.

	CDR-based method	Smartphone-based method
Location information	Cellular base station (mast)	Satellite and cellular base station
Tracking accuracy	Better population coverage	Better location accuracy for individual smartphone users
Location of a person	Lower (around one hundred metres to kilometres), depends on mast density and environment Depends on the use of the phone	Higher (few metres with satellite positioning)
Population coverage	Higher	Lower
People without mobile phones	Not covered	Not covered
People with mobile phones turned off	Not covered	Not covered
People with ordinary mobile phones	Covered	Not covered
People with smartphones location function turned off	Covered	Not covered
People with smartphones location function turned on	Covered	Covered
Analysis of mobility by personal characteristics	Very limited	Yes
Feasibility	Easier and less expensive	More expensive
Personal data protection and privacy	Ensured with anonymous and aggregated data Does not require approval from mobile phone users (approval is given when one registers for the service)	Requires approval from smartphone users
When should be used?	Better option for monitoring mass population movement during large scale restrictions country-wide (hammer phase), or regional (dance phase)	Better to track individuals or smaller population groups for the purpose of monitoring targeted interventions, such as contact tracing or quarantine monitoring