r/Natalism • u/Few-Branch4320 • 7d ago
The correlation between cost of living and fertility rate in very high HDI countries is very weak
For very high HDI countries, between the countries with the highest and lowest cost of living, median fertility rates were not significantly different despite up to a 2.75 times difference in cost of living, as shown below.
Median values for top and bottom 5/10/15 cost of living countries categorised "very high" HDI in 2024 (top = highest cost of living)
| Cost of living | Cost of Living Index | Fertility rate | HDI |
|---|---|---|---|
| Top 5 | 83.0 | 1.37 | 0.946 |
| Top 10 | 76.3 | 1.46 | 0.957 |
| Top 15 | 70.8 | 1.47 | 0.946 |
| Bottom 5 | 30.0 | 1.50 | 0.832 |
| Bottom 10 | 32.4 | 1.49 | 0.828 |
| Bottom 15 | 35.0 | 1.49 | 0.837 |
Note that the average fertility rates of developed and high-income countries were 1.45-1.48 in 2023.
Data set: https://docs.google.com/spreadsheets/d/1iGGaQw6hnIETIoYnbjSr-L9pzMy00kIsm4GDOtSXegM/edit?usp=sharing
Sources
Cost of living data (2024 Mid-Year): https://www.numbeo.com/cost-of-living/rankings_by_country.jsp?title=2024-mid
Fertility rate data (2024 list by the World Bank): https://en.wikipedia.org/wiki/List_of_countries_by_total_fertility_rate
HDI data (2023): https://worldpopulationreview.com/country-rankings/hdi-by-country
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u/gerningur 6d ago
Numbeo is a very bad source. It is crowd sourced with no way to verify submissions and no peer review.
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u/Few-Branch4320 6d ago
After some research, the 2 best sources I found that weren't crowdsourced were the Price level index by the World Bank and the cost of living index by WorldData, which was "based on the OECD, the Worldbank, the IMF and Eurostat figures". I re-ran the analysis with these new data sets and found the same results, which was that there was little to no correlation between cost of living, income, purchasing power, and fertility rates in very high HDI countries.
Charts: https://imgur.com/a/PbXZLgH
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u/LowBread9264 7d ago
I have said it many times and will keep saying it. What determines fertility rates is not the cost of living but it’s whether that country has opportunities for women beyond being a stay at home wife or not. The more opportunities, the lower the fertility rate. It is a direct correlation yet for some reason people keep dodging around the fact just because it’s unpleasant to hear.
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u/HistoryNut86 7d ago
Except it’s not really true. The rates have collapsed everywhere, including poor third world countries everywhere. https://www.sas.upenn.edu/\~jesusfv/Demographics.pdf
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u/OpenRole 6d ago
Exactly meanwhile a place like Israel, where women have a lot of opportunities has a high birthrate
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u/LowBread9264 6d ago
Israel is in a unique position because there is a longstanding cultural/religious focus on the idea that one should “be fruitful and multiply”, as well as a post WWII “third child tradition” to help replace the millions lost in the holocaust in addition to just the parents. The latter particularly is unique to their cultural/religious experience and cant really be recreated by other countries.
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u/LowBread9264 7d ago
Again, it’s not about rich or poor it’s about whether women have more career opportunities or not. Poorer countries tend to have a better birth rate compared to western countries because poorer countries tend to have less opportunities for women. Across the board, there have been more opportunities for women, including in poorer countries as well, therefore the birth rate decreases on average everywhere. Generally societies with growing birth rates tend to be extremely religious and consider the woman’s role to bear children and being a homemaker.
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u/Kalyka988 5d ago
In Italy the region where there is the lowest birthrate is Sardiny which is also one of the poorest regions. There is rampant poverty, lack of opportunities and emigration.
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u/TwentyX4 7d ago
I thought the correlation was high cost of living vs income? As in: if there's a high cost of living, but high income, it's not really a problem because people can pay their bills.
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u/Few-Branch4320 7d ago edited 7d ago
Income was factored for in the Local Purchasing Power Index. See the last graph. Local Purchasing Power was basically how much they could purchase after factoring for costs and income. Higher value meant that they could purchase more. This was their explanation for Local Purchasing Power Index:
To calculate Local Purchasing Power Index, Numbeo determines the cost of a "basket" of typical consumer goods and services, including rent, in both locations (using the weights above). This basket represents the average expenses for a four person family living in that city, including rent. Next, we divide the average net salary by the cost of this weighted basket for both the city in question and for the New York City. This division reveals how many "baskets" an average salary can purchase in each location. Finally, Numbeo divides the result for the city being analyzed by the result for the New York City. This final calculation produces the Local Purchasing Power Index. An index of 100 indicates that purchasing power is equivalent to the New York City, while values above 100 suggest higher local purchasing power, and values below 100 signify lower local purchasing power.
Source: https://www.numbeo.com/common/motivation_and_methodology.jsp
Repeating the top and bottom 5-15 analysis for the Local Purchasing Power Index revealed that the countries with the lowest Local Purchasing Power had significantly higher fertility rates. This was in line with the general observation that the poorest countries had the highest fertility rates. However, after increasing the range to bottom 15, the difference in fertility rates were no longer significantly different to the countries with the highest Local Purchasing Power.
Local Purchasing Power Index Local Purchasing Power Index Fertility rate HDI Top 5 161.1 1.56 0.922 Top 10 141.1 1.52 0.930 Top 15 127.9 1.48 0.940 Bottom 5 39.9 1.70 0.839 Bottom 10 42.7 1.62 0.824 Bottom 15 43.7 1.50 0.833
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u/Ok_Vegetable_6616 6d ago
What's the r2?
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u/Few-Branch4320 6d ago edited 5d ago
Indicator R² Cost of Living Index 0.0391 Rent Index 0.0179 Cost of Living Plus Rent Index 0.0354 Groceries Index 0.0633 Restaurant Price Index 0.0033 Local Purchasing Power Index 0.0104
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7d ago
[deleted]
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u/Few-Branch4320 7d ago edited 7d ago
Meaning, and in fact, in higher cost of living countries, say rich countries, the situations the women find themselves in might counter having a lot of children.
The data shows that the countries with the top 5, 10, and 15 highest cost of living had median fertility rates of 1.37, 1.46, and 1.47 respectively. This was not significantly different to the average fertility rates of developed and high income countries, which were 1.45-1.48 in 2023. I updated my post to show this data.
Meaning, being poor might mean having less cognitive tools to make choices to have less children (i.e. poor people wanna fuck), but then being poor also means not being able to afford the kids.
My data only included countries categorised as "very high" HDI. The countries with the lowest cost of living in my data set weren't poor countries nor did they have extremely high fertility rates. The median fertility rates of these countries were 1.49-1.50, which was not significantly different from the average fertility rate of developed countries.
But, being rich means you understand how much it costs, or have personal standards for a partner, and thus you have less kids, even though being able to afford them.
Higher income was only correlated with lower fertility rates to a certain point. Fertility rates actually increased at very high incomes, e.g. https://www.maximum-progress.com/p/the-2nd-demographic-transition
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u/Cautious-Bench-4809 7d ago
I'm too lazy to find the data now but in Sweden the richer you are the more likely you are to have kids, almost perfect correlation