Correlation and Causation
One can even focus on a particular region. For instance, the counties surrounding Washington, DC are markedly different from the rest of the country:
|More than 90% of residents in counties surrounding the Washington, DC are high school graduates
|Nearly half of the residents of counties surrounding
Washington, DC are college graduates.
|The counties surrounding Washington, DC also have high percentage of residents having a Master's degree or higher.
|The median income in the counties surrounding Washington, DC is above $90,000.
One interesting feature of these counties is their high percentage of foreign-born residents.
|About 1 in 4 residents in counties surrounding Washington, DC is an immigrant.
This figure visually shows the strong linear relation between the radiative forcing and the global temperature response since 1880. It is a simplified version of fig. 3a of [Lovejoy, 2014a, in Climate Dynamics] showing the 5-year running average. Above figure is copied from Yahoo Live Science.
It is true that in the physical sciences, it is more common to see a correlation being presented and understood as a causation. In social sciences, like education, it is much more challenging. Sometimes, it even sounds like a "hen and egg" problem. For instance, do poor neighborhoods lead to poor schools. Or is it the other way around, poor schools leading to poor neighborhoods? More importantly, is there even a causation?