The University of Chicago devolped the first department of sociology in 1892, which became a very dominant factor in American sociological thought. One of its more profound theories was on that of sociological criminology in the city of Chicago. The Chicago School was the first modern crime causation theory in America. It grew from the same base as all of the Chicago School's theories, which was that human behavior is influenced and changed by the physical environment and cultural surroundings, rather than by genetics. The researchers began to study the crime of Chicago using an empirical sociology, wanting to move beyond social philosophy and armchair theory. Though they still studied people through a life-history method, they moved onto an ecological study technique, allowing them to transcend individuality and gain perspective on the characteristics of large groups of people.
The two major methods, then, employed by the Chicago School in their ecological study were the use of official data such as crime data, census reports, and housing and welfare records and the life history mentioned earlier. The life history provided a method of of examining deeply the cumulative factors and events shaping the lives of studied individuals.
Robert Park and Ernest Burgess used these early methods to construct a model of the crime of Chicago. Relying on the data collected, they envisioned the city as a set of concentric circles. The first circle, called the Central Business District, centered in the middle of Chicago, contained the factories and workplaces for most of the people. This circle was also home to the largest number of immigrants, because they had little or no money and needed to live close to where they worked. The second circle was known as the Zone of Transition because businesses and factories were enroaching upon it. The second zone also provided close and cheap housing, and also housed a number of immigrants. The third zone still had high crime rates, but not as high as the first two. This zone, the Zone of Working Man's Homes, contained few or no businesses, no factories, but was mostly made of immigrant workers. As they looked at the crime statistics for the outer circles, they noticed a steady decline in crime the farther from the center they went.
From here, two men named Clifford Shaw and Henry McKay took over. Using Park's data, as well as data of their own indicating that delinquency, tuberculosis, and infant mortality followed the same patterns as crime. They interpreted these observations as meaning that the inner city is a place where, as McKay said: "life is superficial, people are anonymous, relationships are transitory, and kinship and friendship bonds are weak." The called this lack of primary social relationships, social disorganization, and used it as the foundation for their theories of crime. They outlined four principles that constitute social disorganization: low economic status, a mixing of different ethnic groups, high numbers of short term residents, and broken families. From this school of thought, one student, Edward Sutherland, would go on to devolp Differential Association Theory, which would take a deeper look at people's cultural values from their perspective rather than our, American, perspcetive. | 
