# **II. Big Data at Work**

Ecuador's most recent population and national housing census was conducted in 2010 by the National Statistical Institute (INEC acronym in Spanish). It reported the population and number of households in each of Ecuador's 40,681 census sectors. The census cartography is entirely digitized, and polygon shapefiles are also available for each sector. It has been partially updated over the years, and it has been the primary source of information for sampling design of all official surveys like labor, health, and nutrition, and multipurpose surveys, among others. These surveys are representative of the Ecuadoran population residing in the country at different geographical levels. However, the census cartography is not updated enough to capture the recent influx of Venezuelan migrants. Thus, it does not allow to build a representative sample of the migrant and host populations.

Defining a sampling strategy to yield representative samples of host and displaced populations demanded a key innovation: the incorporation of Big Data for the sampling design. The flow of migrants affects mainly urban areas or main cities across the corridor from the northern border with Colombia to the southern border with Peru. The geographical aspect of the phenomenon encouraged the use of Big Data from telecommunication companies because of its accuracy in urban areas. Two leading cell phone providers were contacted in Ecuador to request their collaboration. However, only one of them, Telefonica de Ecuador, had the technical capacity to implement the sampling strategy proposed. Telefonica de Ecuador has vast experience in processing and providing the information requested for this sample.<sup>9</sup> Even though its market share is around 30 percent, which represents approximately 4.6 million clients in Ecuador, it is the only private company with a significant presence in the República Bolivariana de Venezuela's mobile phone market. Thus, it could be expected to attract most Venezuelan consumers seeking to obtain cell phone services in Ecuador.

Telefonica storages around 15 million call detail records (CDR) and 180 million external detail records (xDR) on average per day.<sup>10</sup> For this project, Telefonica processed more than 4.7 billion mobile registries adding up CDR and xDRs for a period between June 2018 and March 2019.<sup>11</sup> Telefonica's database was analyzed to determine how many of the active mobile phones in its database were likely to belong to a Venezuelan who lived in each of INEC's census sectors. The process was conducted in three phases:

- First, each mobile phone in the database was tagged as being active;

- Second, each of the active phones was tagged as likely to belong to a Venezuelan;

> 9 The company has been working since 2017 with the Ministry of Tourism in identifying strategic travel destinations based on the analysis of Big Data (Telefonica de Ecuador, 2018). It has also been working with Quito’s municipality on developing an urban mobility study for the Metro (Telefonica de Ecuador, 2017).

> 10 There are two ways of collecting data: active or passive. The active way is when an event like calls, text, data, etc. is made by the owner of the cellphone and it can be charged to the owner. The coordinates of these events are registered and stored for future analysis. The passive way is when an event is captured by the device and this could not necessarily be charged to the owner. Telefonica de Ecuador (2019)

> 11 There is plenty of evidence in the literature on the use of CDR and XDRs for defining the place of residency of individuals based on the implementation of micro-simulation techniques at the global level and across different issues like employment shocks, infectious diseases, and others. Telefonica de Ecuador (2019).

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