Inflation Shock in Turkey: TÜİK Changes the Formula, Experts Say the Numbers Have Shifted

What was presented as a routine statistical update has detonated into one of Turkey’s most explosive economic debates in years. The Turkish Statistical Institute (TÜİK) has overhauled the methodology used to calculate inflation, and leading economists now warn that the change may reshape not only the numbers, but public perception, monetary policy, and institutional credibility itself.

Starting January 2026, Turkey’s Consumer Price Index (CPI) will be calculated under a new system. While TÜİK insists the move reflects modernization and international standards, critics argue the timing and substance of the changes raise uncomfortable questions.

A Silent Formula Change With Loud Consequences

TÜİK introduced three major revisions: the CPI base year was updated to 2025, consumption items were reorganized under a new classification system, and basket weights are now derived from “Household Final Consumption Expenditures” rather than previous data sources.

On paper, these are technical adjustments. In reality, economists say, they have the power to alter how inflation is experienced, discussed, and politically managed.

Mahfi Eğilmez: “This Is Not Just a Technical Update”

Veteran economist Mahfi Eğilmez was among the first to sound the alarm, arguing that the changes go far beyond statistics.

“The changes made to the CPI are not merely technical updates. They directly affect both the measured level of inflation and how the public perceives it,” Eğilmez said.

He highlighted that items such as cocoa, shaving products, sports event tickets, and parking fees were removed from the inflation basket—even though they remain widely consumed and have seen sharp price increases. More controversially, the weight of housing costs was reduced at a time when rent inflation remains exceptionally high.

Eğilmez posed a pointed question that quickly went viral:
“What could possibly have happened in just one month for prices to rise this much?”

He suggested that price hikes may have been shifted from December into January, making year-end inflation appear lower while pushing the burden into the new year.

He closed his critique with a line that now defines the debate:
“Being able to change approaches is far more important than changing indices.”

Hakan Kara: Central Bank Forecasts Will Not Survive This Shift

Former Central Bank chief economist Prof. Dr. Hakan Kara offered a more measured—but no less consequential—assessment. He acknowledged that the new CPI system may measure inflation at higher levels, yet argued that TÜİK’s willingness to adopt it could strengthen institutional credibility.

“The new CPI index may measure inflation at higher levels. TÜİK’s decision to switch to this index, despite that, actually supports its institutional credibility,” Kara said.

However, Kara warned that monetary policy would not remain untouched. Following the January inflation surprise and the transition to the new index, he expects the Central Bank of the Republic of Turkey (CBRT) to revise its official forecast.

“I believe the Central Bank will raise its year-end inflation forecast from 16 percent to 19 percent,” he said.

Kara, notably, kept his own forecast unchanged at 25 percent—well above official targets.

İris Cibre: “None of This Makes Sense”

Market analyst İris Cibre focused her criticism on the CPI basket weights, arguing that this year’s changes contradict basic economic logic.

“Every year, basket weights change. The general principle is simple: items rising faster than headline inflation gain weight, those rising slower lose weight,” she said.

“But this year, we are seeing the opposite.”

Housing became the most controversial example. Despite rent prices rising by roughly 61 percent, housing’s weight in the basket either stagnated or declined.

“This cannot be explained by subsidies,” Cibre said. “If the old method had been used, inflation would have been much higher. What we are seeing now is already the reduced version.”

She also questioned why the clothing category gained weight even though its price increases remained below headline inflation.

“I simply cannot make sense of this,” she added.

A Warning Hidden in the Central Bank’s Own Words

Cibre also pointed to a technical analysis published on the Central Bank’s official blog, Merkezin Güncesi. According to the blog, the new methodology reduced January inflation by 0.1 percentage points but increased annual inflation by approximately 1 percentage point.

“This blog made me think the Central Bank will revise its 16 percent target,” Cibre said, arguing that the technical impact alone could force a policy recalibration.

Central Bank Confirms Upward Pressure

The CBRT’s own analysis confirmed that the CPI basket now places significantly greater weight on services. Compared to last year, services gained 7.4 percentage points, while energy fell by 3.2 points and core goods by 3.0 points.

Transportation, restaurants, hotels, and other service categories became more dominant, while food experienced a modest overall decline. Processed food gained weight, while fresh fruits and vegetables lost ground.

Central Bank analysts concluded that although the immediate effect slightly lowered monthly inflation, the longer-term impact is unavoidable.

“The upward impact on annual inflation is expected to be approximately 1 percentage point.”

More Than an Inflation Debate

What began as a statistical recalculation has evolved into a broader confrontation over trust, transparency, and economic reality. Inflation is not just a number in Turkey—it is a lived experience, a political fault line, and a measure of institutional credibility.

With formulas rewritten and expectations shifting, one thing is certain: the argument over inflation in Turkey is no longer about mathematics alone. It concerns who controls the narrative and who bears the price.