Aggregated data from Three mobile customers used to monitor Covid-19 travel restriction compliance

The data, described as a Staying Local Indicator bulletin by the Central Statistics Office, was first published last week. File picture: Niall Carson/PA Wire
Mobile phone carrier Three is providing the aggregated movement data of its 2.4m Irish customers to the Department of Health and the CSO in order to monitor compliance with Covid-19 public health and movement restrictions.
The deal between the Department and Three sees the movement data from all handsets on the carrier’s network anonymised and grouped in order to show what proportion of people have been straying more than 10km from home.
The data, described as a Staying Local Indicator bulletin by the Central Statistics Office, was first published last week.
By contrast, more than three quarters of Irish people had stayed local during the first lockdown in April of last year.
The most recent lockdown, which came into operation on December 26, specifies a 5km limit for all people barring essential journeys. The week following that order saw an increase in the number of people remaining in their immediate environs up to 58%.
Mayo was the county with the lowest level of compliance at that time. Less than half the population — just 48.2% of people — stayed within 10km of home.
Updated data issued yesterday showed that two-thirds of people stayed within 10km of home during the week ending January 15, with those in Dublin most likely to remain close to home.
The data-sharing agreement with the Department of Health applies to Three customers alone. Data from phone users on other mobile networks is not being handed over.

Three Mobile would not be drawn on the value of the contract nor the timeframe it covers, describing that information as “commercially sensitive”. However, it’s understood that the CSO will continue to provide the data each Monday for at least the next number of weeks.
Three moved to quell any potential data protection concerns. It said that the data is “collated from anonymised data sets at a macro scale” in order to split the population by local electoral area.
“Only aggregated statistical data is provided to Department of Health. No personal data is provided,” a spokesperson said.
They added that the traffic data complies with Irish legislation requiring that such information be erased “when it is no longer needed”, though the parameters for that requirement were not outlined.
The company currently retains a 35% share of the mobile market in Ireland.
The CSO, in issuing its latest data release, said the data is based on 'anonymised, aggregated, mobile phone activity records.'
"Data from Three Ireland is collated from anonymised data sets at a macro scale, aggregated at Electoral Division and provided to the Department of Health," it said.
"The scope of the arrangement between Three Ireland and the Department of Health is limited to informing the Government response to the Covid-19 pandemic only."