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The small-world network, characterized by special structural properties of high connectivity and clustering, is one of the highlights in recent advances in network science and has the potential to model [...]

Abstract: This study constructs the population migration networks among economic areas in the United States for every consecutive year from 1990 to 2011, and examines their structural properties and population migration dynamics. Various aspects of the structural properties of the networks are explored, including the connectivity, clustering, assortativity and centrality. It was found that these structural properties are mediated by migration dynamics and inter‐area distance, and the patterns of varying structural properties across areas of different connectivity reveal the hub‐and‐spoke structure of the networks. It is evident that there exists tremendous complexity in migration connectivity and dynamics in the US internal migration system. [ABSTRACT FROM AUTHOR]

Many migration studies describe various counties by adopting a priori county typologies, such as the U.S. Department of Agriculture Economic Research Service county typology, which might not be suitable for identifying different age migration patterns of the U.S. counties. This study employs a spatial clustering method that exhaustively compares all U.S. counties on their age migration similarity and spatial proximity to investigate signature age-specific net migration profiles across six decades of U.S. county age-specific net migration data from 1950 to 2010. All of the six-decade data are integrated into a common spatial county boundary on which counties below a population threshold are merged with the nearest county to mitigate the small population problem in net migration rates. As counties are merged by increasing large population thresholds, the Getis-OrdGi* spatial autocorrelation statistic is applied to examine how the spatial migration patterns are affected. It is found that U.S. county age-specific net migration profiles exhibit four signature patterns. Although these patterns are persistent across the past six decades, their spatial distributions have experienced dramatic variation. The small population problem in net migration rates affects the extent and location of the significant spatial migration patterns. [ABSTRACT FROM AUTHOR]

Differences in the reporting units of data from diverse sources and changes in units over time are common obstacles to analysis of areal data. We compare common approaches to this problem in the context of changes over time in the boundaries of U.S. census tracts. In every decennial census, many tracts are split, consolidated, or changed in other ways from the previous boundaries to reflect population growth or decline. We examine two interpolation methods to create a bridge between years, one that relies only on areal weighting and another that also introduces population weights. Results demonstrate that these approaches produce substantially different estimates for variables that involve population counts, but they have a high degree of convergence for variables defined as rates or averages. Finally, the article describes the Longitudinal Tract Database (LTDB), through which we are making available public-use tools to implement these methods to create estimates within 2010 tract boundaries for any tract-level data (from the census or other sources) that are available for prior years as early as 1970. [ABSTRACT FROM PUBLISHER]

Background: Combined ED and police department (PD) data have improved violence surveillance in the UK, enabling significantly improved prevention. We sought to determine if the addition of emergency medical service (EMS) data to ED data would contribute meaningful information on violence-related paediatric injuries beyond PD record data in a US city., Methods: Cross-sectional data on self-reported violence-related injuries of youth treated in the ED between January 2015 and September 2016 were combined with incidents classified by EMS as intentional interpersonal violence and incidents in which the PD responded to a youth injury from a simple or aggravated assault, robbery or sexual offence. Nearest neighbour hierarchical spatial clustering detected areas in which 10 or more incidents occurred during this period (hotspots), with the radii of the area being 1000, 1500, 2000 and 3000 ft. Overlap of PD incidents within ED&EMS hotspots (and vice versa) was calculated and Spearman's r tested statistical associations between the data sets, or ED&EMS contribution to PD violence information., Results: There were 935 unique ED&EMS records (ED=381; EMS=554). Of these, 877 (94%) were not in PD records. In large hotspots >2000 ft, ED&EMS records identified one additional incident for every three in the PD database. ED and EMS provided significant numbers of incidents not reported to PD. Significant correlations of ED&EMS incidents in PD hotspots imply that the ED&EMS incidents are as pervasive across the city as that reported by PD. In addition, ED and EMS provided unique violence information, as ED&EMS hotspots never included a majority (>50%) of PD records. Most (676/877; 77%) incidents unique to ED&EMS records were within 1000 ft of a school or park., Conclusions: Many violence locations in ED and EMS data were not present in PD records. A combined PD, ED and EMS database resulted in new knowledge of the geospatial distribution of violence-related paediatric injuries and can be used for data-informed and targeted prevention of violence in which children are injured-especially in and around schools and parks., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)