A CSO Frontier Series Output- What is this?
What is the Staying Local Indicator?
The Staying Local Indicator (SLI) provides daily estimated percentages of county populations that have stayed local i.e. within 10km of their usual place of residence, averaged over the preceding seven days.
How is the SLI calculated?
The Staying Local Indicator is based on statistical analysis of anonymised, aggregated, mobile phone activity records. Data from Three Ireland is collated from anonymised data sets at a macro scale, aggregated at Electoral Division (ED) and provided to the Department of Health.
How accurate is the SLI?
The SLI is not an exact measure, but a general indication of what percentage of the population is staying local. With 2.4 million users as of August 2020, Three Ireland estimates that it commands a 35% market share. The SLI is premised on the assumption that mobility patterns extracted from the anonymised data of Three Ireland mobile users are broadly representative of those of the wider population. Three Ireland incorporate detailed population statistics from the CSO as part of this process.
Who gets this anonymised statistical analysis?
The statistical aggregates are provided to the CSO with the permission of the Department of Health and under the terms of their agreement with Three Ireland. Only aggregated statistical data is provided to the Department of Health. No personal data is provided.
Is the CSO tracking people’s movements?
No, the statistical information supplied to the CSO is aggregated at ED level. No personal, identifiable data is seen by either the CSO or the Department of Health. At no time do either the Department of Health or the CSO have access to personal or individual level data.
What is the purpose of the data?
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. This data feeds into wider selection of data used as part of the COVID-19 response.
Will this data be used for anything else by the CSO?
No. The CSO is limited to using this data with the permission of the Department of Health to informing the Government response to the COVID-19 pandemic.
What is the role of the CSO in this?
The CSO receives and manages the data on behalf of the Department of Health. The data is deposited by Three Ireland on secure CSO servers.
The role of the CSO is to provide independent statistics on economic, social and general activities and conditions in Ireland. The CSO has published a number of innovative bulletins and publications in response to the current public health crisis. This publication is an example of how aggregate data can be used to indicate mobility during the pandemic and whether Government restrictions impact behaviour.
Why is the CSO publishing this information now?
The CSO is publishing this analysis as part of its role in ensuring we live in an informed society.
Do other statistical agencies use mobile phone data?
Yes, other statistical agencies have used mobile phone data. For example, the Office of National Statistics (UK) has used aggregated mobile phone data to estimate commuting flows. More recently, in response to COVID-19, the Federal Statistics Agency in Germany used mobile phone data to indicate changed mobility behaviour as a result of the pandemic and to analyse the effects of specific restriction measures.
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