Page 147 - Special Topic Session (STS) - Volume 4

STS571 Ossi Nurmi et al.
1. Introduction
During 2016 up to 2018, Statistics Finland carried out the work in two
phases within the context of Eurostat’s ESSNet Big Data –project. The focus in
these projects was on three statistical domains: inbound tourism, outbound
tourism and seasonal population. The first phase in 2017 and 2017 focused on
negotiations with national authorities and MNOs in order to set up such a
process that is feasible from a legislative and technical point of view. The
second phase was to carry out the process, collect data from each MNO and
analyze the results. The chosen approach relies on the operators to process
the data and aggregate it for Statistics Finland. In the current Finnish
legislation, only the operator is allowed to process the raw data using
automatic means. The size of the raw data is also massive, with annual data
consisting of several billions of events per operator.

Figure 1 Process from raw microdata to aggregated trips

The starting point for each operator are the raw data of each of their
subscribers. The subscriptions are associated with sim cards found on mobile
devices. Machine-to-machine sim cards are excluded from the data as they do
not represent the movement of people.

2. Methodology for raw data: processing roaming events to tourism
trips
In case of outbound trips, the raw data consists of roaming events (calls,
sms, mobile data) taking place outside of the subscriber’s home network, in
other words, a foreign country where the event took place. Based on the time
gaps between these events, individual trips of each subscriber can be
recognized.

136 | I S I W S C 2 0 1 9