IBGE and the mayor's office can't agree on the city's population.
jacareacanga ibge population

IBGE and the mayor’s office can’t agree on the city’s population.

At the end of last year, the Brazilian Institute of Geography and Statistics (IBGE) released the latest population estimates for Brazilian municipalities. Populations for one in every four cities have shrunk – a phenomenon that is more noticeable among municipalities of 20,000 or fewer inhabitants. Only 258 cities, out of 5,570, registered growth of at least two percent. Most barely grew.

While the census comes out every 10 years, these estimates are annual. They have been carried out since 1992, taking into consideration other data surveyed by IBGE itself.

Municipal population estimates are calculated from state population projections – which analyze fertility and mortality rates, as well as migration (which was combined with population growth trends observed in the census of 2000 and 2010). For 2017, it shows that Brazil’s fertility rate is 1.67 child per woman, the gross mortality rate is 6.15 deaths per 1,000 people and our net migration flow (that is, people coming into the country minus those leaving the country) was of +8,304 people.

Why is this estimate important? Because it is the data used by the government to allocate chunks of the State and Municipal Fund (money that the federal administration transfers to states and cities). That’s why, every year, some cities file lawsuits to obtain “better” numbers.

The curious case of Jacareacanga

No city, however, has had a wider discrepancy between what was calculated by IBGE and what was granted by a court of law than Jacareacanga, in the state of Pará: 8,000 inhabitants per IBGE, 41,000 per the judicial system.

Created in 1991 and functioning since 1993 in southwestern Pará, Jacareacanga is one of those cities where the army must step in to ensure that Election Day will be safe. Last year, it was the location with the highest temperature in Brazil: 42oC (107oF). In 2016, Federal Prosecutors filed a lawsuit against the municipality for neglecting the education of its indigenous populations – a big part of the city’s population belongs to the Munduruku tribe.

munduruku

Jacareacanga’s Munduruku tribe

Over the past five years, this is what has been placed next to Jacareacanga’s name on IBGE’s table:

Judicial population of Jacareacanga-PA: 41,487 inhabitants. Judicial lawsuit number 798–41.2011.4.01.3902, Jurisdiction of Itaituba-PA

Even if IBGE calculates the estimated population of the city each year, its “judicial population” is always cited next to it. That number, 41,487 people, comes from the 2009 IBGE estimate. In the following year’s census, Jacareacanga was relegated to only 14,040 inhabitants.

The arm-wrestling began in 2011 and, since the wheels of justice turn slowly, it is still continuing. At the time, O Estado de S.Paulo reported on the case as follows:

“Jacareacanga’s mayor Rualien Oliveira de Queiroz (Workers’ Party) complained to IBGE and to a Federal Court. He is willing to chart ten buses to hold a protest in front of IBGE’s office in Santarém [south Pará].”

There’s a flaw in the mayor’s line of thinking. One census can only be compared to another census, since it doesn’t use the same variables as those estimates do. For the census, researchers knock door-to-door. It is a far more reliable survey – in theory, at least. I just couldn’t find any explanation as to how IBGE came up with 41,000 in 2009. The Institute only recognized that it overestimated the numbers.

How much does the overestimation matter?

With a “judicial population” of 41,000, the city is entitled to 16.6 million BRL from the State and Municipal Fund. But if we consider the census numbers, then Jacareacanga would receive only 5.5 million BRL. That’s a difference of 11.1 million BRL.

And that is precisely why the city’s administration headed to court and wants IBGE to prove that it knocked on every door and left no stone unturned. Curiously, ever since 2009, the population estimate for Jacareacanga has fallen – but because of the lawsuit, the judicial population remains at the 2009 numbers: over 41,000 people.

Data from IBGE shows that Jacareacanga is a rather poor municipality. Its GDP was of 157.8 million BRL in 2014, two-thirds of which are represented by the public administration. The agribusiness in the region doesn’t account for 15 percent of the wealth.

GDP per capita varies from 15,000 BRL (with a 10,531 population, as per the latest estimates) or less than 4,000 BRL (per the judicial population).

According to the Central Companies Database, only 801 people in the city were employed in 2015. Considering the census population, 8.3 percent have a formal job. But take the judicial population, and that rate plummets to two percent.

Who is right?

Some data can help us understand what is happening. In 2015, there were 4,930 kids and teens enrolled at schools. For a city with under 10,000 residents, it would mean that half of the population was school-aged students – which seems excessive. But the rate drops to just 12 percent when considering the judicial population – which is too little.

In the 2010 Census, 26 percent of the population fell between 4 and 15 years old. If all children and teens are in school, then the city would have just below 20,000 residents – that’s double the IBGE estimate, but half of what the city claims.

Of course, that number could be inaccurate. Economic events change trends in a city’s population. To find out what is really happening in Jacareacanga, we might need to wait for the 2020 census.


Read the original, in Portuguese.

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BY Marcelo Soares

Marcelo Soares is a Brazilian journalist specializing in data journalism and reader engagement.