There was also a geographical divide between higher and lower skilled areas.
In addition, as certain employees in highly skilled areas may face certain risks, then insurance schemes may be taken out to ensure that such injuries do not cause financial loss to employers as well as to the employees themselves.
In a 2009 paper Mr Glaeser and Matthew Resseger of Harvard University find that in highly skilled areas, city size explains 45% of the variation in worker productivity (it has almost no effect in underskilled cities).
The education level of a county as of 2000 strongly predicts population growth over the last decade.Again, this trend reflects the tendency of skilled areas to generate far higher incomes.
Nato only began the buildup of Afghanistan's police and army in earnest in 2009, and the rapid pace of expansion towards a target of 350,000 meant the police and army would need help for years to come, particularly in highly skilled areas such as bomb disposal, medical evacuation and logistics.
Many of those who wring their hands at the "decline" of manufacturing portray service jobs as inferior, unskilled affairs, although in fact such jobs are increasingly likely to be in highly skilled areas such as teaching, financial services or information technology.Deindustrialisation causes problems in economies unable to absorb the workers released by manufacturing.
I think it is good to have some immigration controls but if there are skilled areas where there is a shortage then there shouldn't be a cap.
There is also good evidence that earnings for low-skill workers are higher in higher-skilled areas and that higher-skilled areas experience faster income and population growth.
For example, Hispanics made employment gains in lower-paid, lower-skilled areas like service and construction.
People who felt that they had been pushed to the margins of society, on low incomes and living in low-skilled areas, were the driving force behind Brexit, according to research from the Joseph Rowntree Foundation.
