When you search for this, you encounter tables ranking countries by IQ. They list a specific number for Turkey and cite an academic study as the source.
This article will not repeat that number. Instead, it does something far more useful: it explains where that number comes from. Once you see the source, you will realize why you shouldn't take it seriously.
Where the numbers come from
Nearly all national IQ rankings on the internet rely on a single source: a data compilation published in the early 2000s and updated later.
This compilation aimed to gather old studies from around the world to generate national averages. The idea sounds reasonable. The execution, however, suffers from serious flaws.
Issue 1: Unrepresentative samples
To calculate a country's average, you need a representative sample: balanced across regions, education levels, and age groups.
Most data in the compilation fails to meet this standard. Some "national averages" were calculated from groups of just a few dozen people. Others came from a single school in one city, or specialized groups in specific institutions.
Calculating a national average from such a sample is like looking at the average income of one neighborhood to calculate a country's total income.
Issue 2: Some numbers were never measured
This is the least known and most striking part.
For some countries in the compilation, no data existed at all. Their values were estimated from the averages of neighboring countries.
This means some numbers you see in the table are not the result of a measurement, but of interpolation. Yet they are displayed with the same precision as measured values.
Issue 3: Tests and years are not comparable
The studies in the dataset used different tests, conducted in different years and across different age groups.
- Data for one country might come from the 1970s, while another's is from the 2000s.
- One study evaluated children, while another tested adults.
- The tests used vary, and some were never normed for that specific country.
The most critical issue here is the Flynn effect: average IQ scores rose by about 3 points per decade throughout the 20th century. If you directly compare a country measured in 1970 with one measured in 2005, a large part of the difference comes down to the year of measurement alone.
Issue 4: The test itself is culture-bound
IQ tests are standardized for the specific society where they are administered. Applying a test developed in one society to another where it was never normed creates serious methodological problems.
Test questions—especially verbal and general knowledge sections—assume a specific educational tradition and daily life experience. Even abstract shape tests are not entirely culture-free: the habit of thinking through abstract patterns is largely acquired through schooling.
What academic evaluations say
Researchers who re-analyzed this dataset identified major selection and sampling issues, particularly in regions with the lowest data quality. Published critiques demonstrated that several country estimates in the compilation are scientifically indefensible.
Today, the consensus in the field is clear: these tables are not a valid source for comparing national cognitive capacity. Yet they remain the most circulated data online because they are simple, rankable, and easy to share.
Can national IQ really not be measured?
It can be measured—but the requirements are demanding:
- A sample representing the national population, balanced by region and socioeconomic background
- A test normed specifically for that country
- Standardized testing conditions
- Comparison data collected during the same timeframe
No comprehensive, comparable international IQ study meeting these criteria currently exists. What exists are isolated norming studies in individual countries, which were not designed to be compared against one another.
A better dataset to examine
If you want to compare cognitive performance across countries, a much more methodologically sound source exists: PISA.
PISA offers clear advantages:
- Administered in the same year, to the same age group (15-year-olds), using the same tool
- Sample selection is standardized and audited
- Results are publicly released
- Data is reported alongside socioeconomic variables
Turkey's PISA 2022 results: math 453, reading 456, science 476. The OECD averages are 472, 476, and 485, respectively. This puts Turkey below average in all three areas.
However, keep in mind: PISA does not measure intelligence; it measures educational outcomes. The two are related, but they are not the same. For a detailed breakdown, read our article on what PISA is and why Turkey scores below average.
Why national averages are not very useful
Methodological issues aside, such numbers have limited practical value.
Within-country variation is far greater than differences between countries. The gap between the lowest and highest scoring individuals in any single country vastly exceeds the differences between country averages.
Knowing a country's average tells you almost nothing about a randomly selected individual from that country. Statistically, it provides very little information.
Furthermore, average scores correlate strongly with changeable conditions: nutrition, healthcare access, years of schooling, and early childhood education. These are not fixed traits—and the Flynn effect proves that scores increase as these conditions improve.
Frequently asked questions
Is the number listed for Turkey actually wrong?
To call a number "wrong," an accurate number would first need to exist. The issue is that the number is not based on reliable measurement. It isn't just wrong—it is groundless.
Why are these lists so widespread?
They are simple, easy to rank, and spark debate. Methodological critiques, on the other hand, are complex and less shareable.
Are there real differences between countries?
There are measurable differences in educational outcomes, documented by tools like PISA. These differences stem largely from educational systems, economic conditions, and public health indicators.
How can I find out my own score?
National averages do not determine individual ability—your own score does. For a rough estimate, take our free IQ test, or read our guide on how to find out your IQ level for an official evaluation.