The theories of Jane Jacobs, American intellectual and urban activist in New York during the mid-20th century, were published in her book The Death and Life of Great American Cities.

Researchers Xavier Delclòs and Carme Miralles used census and land registry data, as well as geographical information systems, to gather six variables and create an index of analysis called JANE, and finally design its methodology.

"The JANE index helps to understand two key elements: firstly, the way in which cities are designed and built can create environments with very different levels of street life, and secondly, in the specific case of Barcelona, one can find areas with high levels of street life in peripheral and traditionally poor districts, and therefore not only in the centre of the conurbation", Xavier Delclòs points out.

Urban Vitality Not Only In Historic Centres

The distribution pattern of urban vitality identified by researchers can be explained largely by the presence of cities and historic centres in the conurbations analysed, which fulfil the requirements proposed by Jane Jacobs.

Thus, there are three "corridors" of vitality, spreading out from the centre of Barcelona: one towards the district of Gràcia - which constitutes the vertebrate of vitality of the whole conurbation, another towards the northeastern border of the town of L'Hospitalet de Llobregat and a third one veering north towards the districts of Horta-Guinardó and Sant Andreu.

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