The following visualisation will compare the location of gun shootings within Chicago's communities with socio-economic variables. Mapping out the precise location of gun violence alongside different factors shows significant spatial variation in where these events occur. The tool allows a user to click on a variable to obtain a statistical analysis of how gun shootings compare across Chicago's community areas.
Gun violence is one of the main problems in the US, a country that sits at 11th place in the international rank of gun-related deaths. This violence occurs disproportionately in urban regions: in 2015 just 20 cities – covering nearly 9% of the total US population – accounted for almost 25% of gun-related deaths. Chicago, one of the most violent cities in the US, registered more shootings than New York City and Los Angeles combined.
So what are the main theories that relate to gun crime according to the literature ?
On the basis of the literature we have chosen the following variables for the analysis:
The first attribute data are the records of all gun incidents in Chicago in 2015, which are collected and maintained by the Gun Violence Archive. The geographical coordinates of these incidents are provided for use in vector representation as points. Three factors have been considered when gathering the data needed for this research. Firstly, they should be the data that has been released by the official relevantÂ organisations to ensure the data sources are reliable. Secondly, they must be related to the comparable years influencing the gun crime incidents that we are analysing, and finally their scale should be equivalent and relatable to the boundary files.
For creating a database, MySQL software is used, which allows the import of various tables into the available server (dev.spatialdatacapture.org). Also with MySQL scripts the tables can be cleaned, amended and joined, per Census Tracts and grouped for the larger Community Areas. Moreover, by data cleaning the data is ready for the analysis process.
Two methods of analysis conducted on the data related to the gun shooting crime in Chicago, namely regression and cluster analysis. Firstly, different factors are considered to find any relationship between the gun shooting incident rate in Chicago's communities and the demographic and socioeconomic factors. For finding the said relationship, we perform simple linear regression. Next, we decide about the strength and significance of the regressions with looking at the r-value and P-value. To analyse if gun incidents were occurring at a higher rate in places of common characteristics, cluster analysis is used to further analyse the relationship between our variables and the incident rate. Incident rate is not used in the algorithm but analysed against the output. K-Means clustering algorithm is used to ensure all areas are assigned a cluster for comparison against gun incidents across the whole city.
Once analysis is completed we need to set up a node.js program that would provide JSON files to return our desired data, through MySQL commands, for use in our website. Endpoints are created for boundary data as GeoJSONs, incident locations and characteristics, and our explanatory variables for varying scales.
The findings of this research have been presented by creating a website that presents information through different formats, namely map, graphs and charts and text.
The necessary texts for this website related to research objectives, analysis, explanations, methodology etc. has uploaded in certain html files which their style has improved with supporting css files.
After testing simple linear regressions between incident rate and different demographic and socioeconomic factors in Chicago's communities, it seems that there are quite high direct correlations between gun shooting crime in communities and housing vacant rate, rate of people with less than high school diploma, rate of rental occupied and mental health problems. Also, there are a negative correlation between gun shooting incidents and per capita income, rate of married families with children and median year of buildings. Our cluster analysis puts all communities in to one of 4 clusters, identified by the similarity of variables. We find 258 of the 409 incidents contained within one cluster. This means 63.1% of incidents occur within 24.7% of the population. Without using the incident rate within the cluster analysis, we find the clusters experience very different proportions of the incidents, and similarity of characteristics finds the areas where there is much more gun violence.
Geographic level: Census Tract (by State--County)
Dataset: 2015 American Community Survey: 5-Year Data [2011-2015, Block Groups & Larger Areas]
1. Family Type by Presence and Age of Own Children Under 18 Years
2. Educational Attainment for the Population 25 Years and Over
3. Per Capita Income in the Past 12 Months (in 2015 Inflation-Adjusted Dollars)
4. Occupancy Status
6. Median Year Structure Built
2) Centre for Disease Control and Prevention
Data resource: Behavioral Risk Factor Surveillance System (BRFSS): 2014.
Numerator: Respondents aged >18 years who report 14 or more days during the past 30 days during which their mental health was not good.
Denominator: Respondents aged >18 years who report or do not report the number of days during the past 30 days during which their mental health was not good (excluding those who refused to answer, had a missing answer, or answered 'don't know/not sure').
3) Chicago Data Portal
Census Tracts (2010)
Chicago Community Areas
4) Gun Incidents
Data of individual and census tract aggregates gun incidents for 2015 available from the Guardian, acquired from Gun Violence Archive.
5) Map provided by Google Maps API
The "Chicago's Gun Violence" project was developed by the members above for the Spatial Data Capture, Storage & Analysis module as part of the MSc in Smart Cities & Urban Analytics at UCL, London.