Although Estonia showed a strong relationship between an increasing fertility rate and an increasing GDP per capita, the same cannot be said for the world as a whole. By looking at every country that records their data, it can be said that countries who have a lower fertility rate tend to have a higher GDP per capita, whereas countries with a higher fertility rate have a lower GDP per capita. This being said, in 2011, there was a -0.44 correlation worldwide between fertility rates and GDP per capita. Comparing Estonia and the worldwide data, it could be said that there are compounding variables that are influencing the relationship (or no relationship) between fertility rates and the GDP per capita.
Countries who spend more money per person on healthcare tend to receive benefits others would not experience. The higher spending usually means that everyone receives a many health benefits with a great healthcare system. But could Estonia's health expenditures between 1995 and 2010 show a positive relationship with their fertility rate?
The answer is yes. By comparing Estonia's health expenditure per capita with their fertility rate, it is shown that there is definitely a positive correlation. To be exact, this correlation is 0.955, which shows that there is a strong positive correlation between the two variables. This could mean that with an increasing health expenditure per capita could cause the GDP per capita to rise as well.
A country's GDP is representative of not only the economic growth experienced during a timeframe, it also demonstrates a country's standard of living. But the same question of whether or not there is a confounding variable that influences the data haunts Estonia's GDP per capita. Could Estonia's GDP per capita actually be influenced by the adjusted net national income?
The answer here is also yes. There is a strong positive correlation, at 0.981, between an increasing adjusted national net income and GDP per capita. Because of this strong correlation between net national income and GDP per capita, it could also be theorized that an increasing net national income could also have an effect on an increasing fertility rate.
So in the end, it cannot 100% proven that an increasing fertility rate directly determines a country's GDP per capita. Not every country is the same, which can be seen by comparing Estonia's graph in the first post to the animated graph in this post.
Personally, I agree with the points that Jonathan Last brings up in his article about how an increase in fertility rates means that there are more people to innovate, which leads to an increase in GDP per capita and a larger work force. Though at this point, I am just not sure as to how much of an influence a rising fertility rate has on a country's GDP. To make Last's theory true, I feel as though a country has to already have a strong financial backbone (like Estonia) for a factor like fertility rates to have an impact on which way the GDP moves. So in countries in the European Union, rising fertility rates could in time increase their GDPs per capita, but in places like Africa and Asia, we still have a long way to go financially before we can link fertility rates to their financial success.