Gambia – Data from 2 billion phone calls discreetly accessed countrywide in a covid-19 related study
As the government of The Gambia imposed a confinement in the country on 22nd March lasting May 2020, a discreet study was conducted on data obtained from 2 billion phone Call Detail Records (CDR) of mobile phones users in the country. Two major operators capturing 70 percent of the national telecom market share availed the data. The study also looked into the aggregated and anonymized cell-phone data of the “guinea pigs” phone users and then concluded that the poorest wards in The Gambia suffered the most from the two months lockdown.
A priori, the intention of the study appears unharmful and not malicious as the experts, Moritz Meyer a Senior Economist, Poverty and Equity GP at the World Bank and Erwin Knippenberg a Phd candidate, were assisted by officials of the Gambia Public Utilities Regulatory Authority (PURA) and the Gambia Bureau of Statistics (GBOS). The study was also blessed by the Trust Fund for Statistical Capacity Building and the World Bank DEC-DIME Group.
Changes in weekly population inflow across time and districts
This said the unknown secret access and manipulation of Call Detail Record (CDR) data of 2 billion phone calls from mobile subscribers in a country like The Gambia raises privacy concerns as regards the protocols and guidelines that guaranteed confidentiality of the data everyone involved in the study had accessed. Sources with knowledge on the issue however assured The Chronicle that thanks to the study, “PURA was able to build a secure CDR data pipeline in The Gambia and used that data for analysis to have a better insights into the effects of the COVID-19 outbreak on population dynamics“.
Findings show a disparate impact of Covid-19 between rural and urban areas
The Chronicle learnt that upon the imposition the nationwide lockdown on March 22nd, there was a substantial out-migration from the densely populated coastal urban areas into rural areas inland as people leave the Greater Banjul Area. Some results in the study suggest that “Areas with a high percentage of international calls also have a large concentration of families with international migrant workers. The out-migration intensified between April 19-25th, the beginning of Ramadan, likely because people opted to stay with relatives in rural areas”. The pattern of out-migration continued until mid-May, when we people gradually reverse the trend from rural areas to The Greater Banjul as Ramadan ends and economic activities resume before Koriteh. Findings show how population movement dynamics shift on a weekly basis.
Using the International Mobile Equipment Identity (IMEI) they got prior to the confinement and thanks to PURA, the researchers looked to know if the internal migration disruptions affect different populations. They matched movement patterns with district- or ward-level information on poverty from the 2015 national household survey availed by GBOS.Changes in weekly population inflow across wards with highest and lowest poverty rates
The researchers noticed that “The wards with the highest proportion of poor households see the largest disruption to their mobility in terms of both inflow and outflow relative to wards with the lower proportion of poor households. Mobility dropped by as much as 25%, particularly during Ramadan period, with some small spikes before and after Ramadan, and then recovered gradually”. The result suggests that the poorest wards suffered the most from the lockdown, perhaps because they rely on economic activities that were most affected by social distancing policies (informal trade, markets, etc.).
The Chronicle has also learnt that while Covid-19 might have serve as an excuse for the study, plans are underway to involve other mobile phone operators in further researches. According to our sources, that will help PURA access data collected by the private sector to ensure compliance and encourage a system building for insightful government decision making.