A new study claims that a high concentration of engineers is one of the key factors enabling some of the leading US cities to excel economically.

Research conducted by economist Patrick Jankowski of the Greater Houston Partnership indicates that there is a significant correlation between between the per capita ratio of engineers in a given region's workforce and its economic prosperity.

This principle is best exemplified by California's Silicon Valley, which has the highest per capita number of engineers out of any major city in the United States.

The Valley's remarkable concentration of elite engineering talent - 45 out of every 1,000 employees in the area is an engineer - has played a pivotal role in supporting its hi-tech industries, making it the most affluent metropolitan area in the United States.

Houston comes in second on the list of American cities with the highest concentration of engineers, with around 22.4 engineers per 1,000 employees. The city is also home to the second largest number of engineers in the United States at a total 49,000 professionals in the field, a great number of whom provide their service's to Houston's burgeoning energy sector.

The energy sector has recently emerged as one of the most prolific employers of engineering talent in the United States, as well as one of the best paying areas for professional engineers. This has particularly been the case in the wake of the North American shale gas boom, which has shaken up global energy markets and made the United States a key supplier of fossil fuels.

For this reason Bakersfield - long renowned as the oil capital of California, has the ninth highest per capita concentration of engineers in the country despite its comparatively modest population of just under 350,000.

Although a high number of engineers invariably bodes well for a city's prosperity if their presence is associated with either the hi-tech or energy sectors, in some areas a large pool of engineering talent is accompanied by economic unease or even malaise as a result of recent weakness in America's manufacturing sector.

This is the case with Wichita, Kansas, which is home to the United States' third highest per capita level of engineering professionals, at 21 engineers out of every thousand employees. Boeing's recent decision to scale back its operations in the area, however, has darkened the economic prospects of the city, which is highly dependent upon aerospace manufacturing and advertises itself as the "air capital of the world."