Nigeria needs to rebase its telecoms subscriber measurement methods in the same way it has done for its gross domestic product (GDP) statistics, says a local technology expert.

On Sunday, Nigeria overtook South Africa to become Africa’s biggest economy after the West African country rebased its GDP calculations to include sectors such as Nollywood and even mobile operator revenues. The recalculated GDP figures revealed that Nigeria’s GDP for 2013 numbered $509 billion.

But while Nigeria’s previous GDP figures had been underestimating the size of its economy, an expert says that the Nigerian Communications Commision (NCC) may be exaggerating the size of the West African nation’s mobile subscriber numbers.

According to the NCC’s February 2014 statistics, Nigeria has 167,371,945 GSM subscribers, 7,620,525 CDMA users and 2,238,458 fixed lines.

“They should have data on exact users and not just SIM cards,” Nigeria technology expert, commentator and ICT for Development (ICT4D) consultant. 'Gbenga Sesan, has told ITWeb Africa.

“Reporting on users, instead of SIM cards, will make the methodology more accurate,” he said.

The sale of dual-SIM mobile phones in Nigeria by the likes of Nokia and telecoms player Etisalat further means that Nigerians switch networks regularly to capitalise on call and data promotions.

This factor on its own could mean that fewer Nigerians have access to mobile phones than previously thought.

But the NCC maintains that Nigeria has 177,230,928 connected lines and a teledensity rate of 92.14%, as per its February 2014 figures.

“It’s also not in the sector’s interest to report 91.4 teledensity as this would mean market saturation - which isn’t the case in reality,” Sesan told ITWeb Africa.

“Saturation means other markets are more attractive to investors, and Nigeria loses,” Sesan said.