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Large Numerical Discrepancies Found in Central Bank and Statistical Center of Iran Data

May 22, 2023

Iran Open Data’s investigation shows a large numerical discrepancy between macroeconomic data reported by the Central Bank and the Statistical Center of Iran. Over the past two years, for example, the difference between their Gross Domestic Product (GDP) calculations is about 2 quadrillion Tomans (about $38.24 billion, at an exchange rate of 52,300 Tomans/$1). 

These calculations use the current GDP value, so the base year fault and “constant price based on inflation” error, both common mathematical errors, should not affect the calculations. 

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This statistical discrepancy is not limited to the calculation of the GDP. In economic growth and inflation indices, there is also a significant and noticeable difference between the numbers and figures presented by the two authorities. At times, the difference in inflation rates between these two organizations is close to 20%. 

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As of the publication of this report (15 Ordibehesht 1402), the Statistical Center of Iran had not yet announced the inflation statistics for the last month and annual rate for last year.

In the last quarter of last year, the Central Bank and the Statistical Center of Iran suspended the publication of real estate transaction figures, as well as the average housing prices and rental rates in Tehran and other urban regions. After years of not releasing inflation data, the Central Bank recently released incomplete inflation data for last year. 

This inconsistency in the publication of economic statistics has been criticized by economic experts.

Iran Open Data’s research reveals that the discrepancy in inflation figures provided by the  Statistical Center of Iran and the Central Bank has increased since 1396 in three indicators: monthly inflation, point-to-point inflation, and annual average inflation.

This discrepancy is more pronounced during periods of accelerated inflation and high price fluctuations.

The Central Bank reports changes in the general level of prices of goods and services solely in urban areas of Iran. The comparative data in the triple charts has been extracted from the urban inflation rate data provided by the Statistical Center of Iran.

These charts clearly indicate that during the inflation peaks between 1395 and 1401, the difference in the inflation numbers reported by the two institutions had increased.

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This discrepancy is not limited to inflation. The GDP estimates of the two institutions are also significantly different. 

Iran Open Data research shows a discrepancy of as much as 34% in certain years from 1385 to 1401 (2006-2022).

To examine these figures, current GDP has been used to bypass the base-year difference issue.

As indicated in the chart below, the statistical discrepancy of the GDP intensified after 1396 (2017).

During the period between 1385 and 1401 (2006-2022), the GDP figures reported by these institutions varied the least, less than 10%. However, this discrepancy is the highest, about 34%, between 1398 and 1400. 

These discrepancies also occur in reports on specific sectors of the economy. This fact highlights operational issues of the departments responsible for this research, raising questions about the accuracy and reliability of these reports.

There is a significant discrepancy in the 9-month economic report of 1401 (2022) published by these organizations, which is the latest published GDP report. 

According to the calculations of the Central Bank, Iran's economic growth at the end of last fall was 3.7%. However, the Statistical Center reported 3.3%. Nevertheless, the growth rates and sector report details are significant.

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For example, the Central Bank reported that the agricultural sector showed a growth of 1.1% last year. However, the Statistical Center of Iran reports 4.3%. Similarly, the industrial sector has a 3 percentage point discrepancy.

The two organizations’ report on the construction sector varies by 3% for this period. The Statistical Center reports -2.2%, while the Central Bank reports 0.6%. 

Estimating the GDP requires the distribution of questionnaires and the collection of statistical samples. 

These large GDP discrepancies result from variations in data sampling and responses to household and private sector questionnaires. Data about the public sector, exports, and imports that rely on official data is not immune to significant differences. 

The expenditure discrepancy is also significant. The Statistical Center reports the gross fixed capital formation to be 7.7%, while the Central Bank reports 1.2%, in 1401. 

The Statistical Center reports that the public sector expenditure growth is 5%, while the Central Bank reports -0.7%. 

The capital formation growth report also varies by 13.3%. The Central Bank reports 19.7%, while the Statistical Center reports 6.4%. 

Hiding data, discontinuing their publication, irregular presentation, and the lack of a publication calendar have become common practice among key Iranian economic institutions. The resulting statistical discrepancies create ambiguity, increase the risk of economic turmoil, and cause further uncertainty.