Use of Density Equalizing Map Projections (DEMP) in the analysis of childhood cancer in four California counties. Revision 2

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In studying geographic disease distributions, one normally compares rates among arbitrarily defined geographic subareas (e.g. census tracts), thereby sacrificing the geographic detail of the original data. The sparser the data, the larger the subareas must be in order to calculate stable rates. This dilemma is avoided with the technique of Density Equalizing Map Projections (DEMP). Boundaries of geographic subregions are adjusted to equalize population density over the entire study area. Case locations plotted on the transformed map should have a uniform distribution if the underlying disease rates are constant. The present report describes the application of the DEMP technique to ... continued below

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24 p.

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Merrill, D.W.; Close, E.R.; Holmes, H.H. & Selvin, S. October 1, 1995.

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Description

In studying geographic disease distributions, one normally compares rates among arbitrarily defined geographic subareas (e.g. census tracts), thereby sacrificing the geographic detail of the original data. The sparser the data, the larger the subareas must be in order to calculate stable rates. This dilemma is avoided with the technique of Density Equalizing Map Projections (DEMP). Boundaries of geographic subregions are adjusted to equalize population density over the entire study area. Case locations plotted on the transformed map should have a uniform distribution if the underlying disease rates are constant. The present report describes the application of the DEMP technique to 401 childhood cancer cases occurring between 1980 and 1988 in four California counties, with the use of map files and population data for the 262 tracts of the 1980 Census. A k`th nearest neighbor analysis provides strong evidence for geographic non-uniformity in tract rates (p < 10{sup {minus}4}). No such effect is observed for artificial cases generated under the assumption of constant rates. Work is in progress to repeat the analysis with improved population estimates derived from both 1980 and 1990 Census data. Final epidemiologic conclusions will be reported when that analysis is complete.

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24 p.

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OSTI as DE96002438

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  • 1995 CDC/ATSDR symposium on statistical methods: small area statistics in public health: design, analysis graphic and spatial methods, Atlanta, GA (United States), 25-26 Jan 1995

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  • Other: DE96002438
  • Report No.: LBL--36630-Rev.2
  • Report No.: CONF-950168--2-Rev.2
  • Grant Number: AC03-76SF00098
  • DOI: 10.2172/10117532 | External Link
  • Office of Scientific & Technical Information Report Number: 132696
  • Archival Resource Key: ark:/67531/metadc623003

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  • October 1, 1995

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  • June 16, 2015, 7:43 a.m.

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Merrill, D.W.; Close, E.R.; Holmes, H.H. & Selvin, S. Use of Density Equalizing Map Projections (DEMP) in the analysis of childhood cancer in four California counties. Revision 2, article, October 1, 1995; California. (digital.library.unt.edu/ark:/67531/metadc623003/: accessed August 16, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.