Spatial regimes: dynamics of intentional homicides in the city of Sao Paulo between 2000 and 2008

Objective. To identify the existence of spatial and temporal patterns in the occurrence of intentional homicides in the municipality of Sao Paulo (MSP), Brazil, and to discuss the analytical value of taking such patterns into account when designing studies that address the dynamics and factors associated with the incidence of homicides. Methods. A longitudinal ecological study was conducted, having as units of analysis 13 205 census tracts and the 96 census districts that congregate these sectors in Sao Paulo. All intentional homicides reported in the city between 2000 and 2008 were analyzed. The gross homicide rates per 100 000 population was calculated as well as the global and local Bayesian estimates for each census tract during the study period. To verify the possibility of identifying different patterns of the spatial distribution of homicides, we used BoxMap and Moran's I index. Results. The homicide trends in the city of Sao Paulo in the last decade were not homogeneous and systematic. Instead, seven patterns of spatial distribution were identified; that is, seven spatial regimes for the occurrence of intentional homicides, considering the homicide rates within each census tract as well as the rates in adjacent tracts. These spatial distribution regimes were not contained within the limits of the census tracts and districts. Conclusions. The results show the importance of analyzing the spatial distribution of social phenomena without restriction of political and administrative boundaries.

Homicide and public security indicator trends in the city of Sao Paulo between 1996 and 2008: a time-series ecological study

The scope of this paper was to analyze the association between homicides and public security indicators in Sao Paulo between 1996 and 2008, after monitoring the unemployment rate and the proportion of youths in the population. A time-series ecological study for 1996 and 2008 was conducted with Sao Paulo as the unit of analysis. Dependent variable: number of deaths by homicide per year. Main independent variables: arrest-incarceration rate, access to firearms, police activity. Data analysis was conducted using Stata. IC 10.0 software. Simple and multivariate negative binomial regression models were created. Deaths by homicide and arrest-incarceration, as well as police activity were significantly associated in simple regression analysis. Access to firearms was not significantly associated to the reduction in the number of deaths by homicide (p>0,05). After adjustment, the associations with both the public security indicators were not significant. In Sao Paulo the role of public security indicators are less important as explanatory factors for a reduction in homicide rates, after adjustment for unemployment rate and a reduction in the proportion of youths. The results reinforce the importance of socioeconomic and demographic factors for a change in the public security scenario in Sao Paulo.

Evolução dos homicídios e indicadores de segurança pública no Município de São Paulo entre 1996 a 2008: um estudo ecológico de séries temporais

OBJETIVO: analisar a associação entre homicídios e indicadores de segurança pública no MSP entre 1996 e 2008, após controle para taxa de desemprego e proporção de jovens na população. METODOLOGIA: estudo ecológico de série temporal, tendo como unidade de análise o Município de São Paulo (MSP), entre 1996 e 2008. Variável dependente: óbitos por homicídio; variáveis independentes principais: taxa de aprisionamento-encarceramento (TAE), o acesso a armas de fogo (AAF), e a atividade policial (ATP). A análise dos dados foi realizada com o software Stata.IC 10.0. Modelos de regressão binomial negativa simples e multivariados foram construídos. RESULTADOS: A análise univariada demonstrou associação entre óbitos por homicídio e TAE e entre óbitos e ATP. O AAF não se mostrou associado à redução no número de óbitos por homicídios (p > 0,05). Após ajuste houve perda da significância na associação com ambos indicadores de Segurança Pública. CONCLUSÕES: No MSP o papel das ações de segurança pública perdem importância como fatores explicativos para a redução nos níveis de homicídios após controle para taxa de desemprego e redução na proporção de jovens. Os resultados reforçam a importância dos fatores socioeconômicos e demográficos para a mudança no cenário da segurança em São Paulo.