Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social Data

This study evaluates the modified areal weighting by control zones method (MAW-CZ) often involved in downscaling social data from a large spatial mesh, to a smaller mesh. This method has been extensively used in literature but the impossibility, until recently, of accessing individual data makes it...

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Main Authors: Najla Touati, Wilda Jean Baptiste, Julia Hidalgo
Format: Article
Language:English
Published: European Association of Geographers 2025-07-01
Series:European Journal of Geography
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Online Access:https://eurogeojournal.eu/index.php/egj/article/view/824
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author Najla Touati
Wilda Jean Baptiste
Julia Hidalgo
author_facet Najla Touati
Wilda Jean Baptiste
Julia Hidalgo
author_sort Najla Touati
collection DOAJ
description This study evaluates the modified areal weighting by control zones method (MAW-CZ) often involved in downscaling social data from a large spatial mesh, to a smaller mesh. This method has been extensively used in literature but the impossibility, until recently, of accessing individual data makes it so that it has not been evaluated.  In this study it is applied to two case studies, Toulouse and Grenoble-Alpes Metropoles, using the census INSEE data at the IRIS scale and the building islet or topographical reference units (RSU) scale. The study found that 27.2% of RSUs in the Toulouse metropolis and 21.9% in the Grenoble-Alpes metropolis are inhabited, with mean populations of 122 and 116 residents, and maximum populations of 2,429 and 6,451 residents, respectively in 2018. The chosen downscaling approach introduces small errors for small and medium-sizedRSUs. For example, 94%, 78%, and 72% of RSUs of <100, 101–255, and 256–500 inhabitants, respectively, are correctly classified by the modified areal weighting by control zones method in the Toulouse Metropole. However, there are significant differences for the most populated RSUs (the performance decreases to 60% for RSUs with more than 500 inhabitants), with this category having a representativeness of 8.4% and 7.2% of the total number of inhabited RSUs in the Toulouse and Grenoble-Alpes metropoles, respectively. The spatial distribution of the biased RSUs are nevertheless homogeneous throughout the two territories. These discrepancies are due to both the upscaling/downscaling methods used and the nature of the data (points in the upscaling and polygons in the downscaling). Highlights: • Population is downscaled from the census IRIS scale, to the RSU scale. • Modified areal weighted by control zones approach is evaluated. • Downscaling performs for small and medium-sized RSUs, <500 inhabitants with errors between 2 and 28%. • RSUs with >500 inhabitants — where errors reach 40% — represent <10% of inhabited RSUs in both case studies.
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spelling doaj-art-d4d7ac01e0464df2a4e9f94d2b792dbd2025-08-02T08:09:35ZengEuropean Association of GeographersEuropean Journal of Geography1792-13412410-74332025-07-0116210.48088/ejg.n.tou.16.2.268.285Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social DataNajla Touati0Wilda Jean Baptiste1Julia Hidalgo2LISST, UMR 5193, Toulouse Jean Jaures University, 5 allée A. Machado, Toulouse, 31058, FranceLISST, UMR 5193, CNRS, 5 allée A. Machado, Toulouse, 31058, FranceLISST, UMR 5193, CNRS, 5 allée A. Machado, Toulouse, 31058, France This study evaluates the modified areal weighting by control zones method (MAW-CZ) often involved in downscaling social data from a large spatial mesh, to a smaller mesh. This method has been extensively used in literature but the impossibility, until recently, of accessing individual data makes it so that it has not been evaluated.  In this study it is applied to two case studies, Toulouse and Grenoble-Alpes Metropoles, using the census INSEE data at the IRIS scale and the building islet or topographical reference units (RSU) scale. The study found that 27.2% of RSUs in the Toulouse metropolis and 21.9% in the Grenoble-Alpes metropolis are inhabited, with mean populations of 122 and 116 residents, and maximum populations of 2,429 and 6,451 residents, respectively in 2018. The chosen downscaling approach introduces small errors for small and medium-sizedRSUs. For example, 94%, 78%, and 72% of RSUs of <100, 101–255, and 256–500 inhabitants, respectively, are correctly classified by the modified areal weighting by control zones method in the Toulouse Metropole. However, there are significant differences for the most populated RSUs (the performance decreases to 60% for RSUs with more than 500 inhabitants), with this category having a representativeness of 8.4% and 7.2% of the total number of inhabited RSUs in the Toulouse and Grenoble-Alpes metropoles, respectively. The spatial distribution of the biased RSUs are nevertheless homogeneous throughout the two territories. These discrepancies are due to both the upscaling/downscaling methods used and the nature of the data (points in the upscaling and polygons in the downscaling). Highlights: • Population is downscaled from the census IRIS scale, to the RSU scale. • Modified areal weighted by control zones approach is evaluated. • Downscaling performs for small and medium-sized RSUs, <500 inhabitants with errors between 2 and 28%. • RSUs with >500 inhabitants — where errors reach 40% — represent <10% of inhabited RSUs in both case studies. https://eurogeojournal.eu/index.php/egj/article/view/824Downscaling social dataupscaling social dataaggregationdisaggregationmeshspatial analysis
spellingShingle Najla Touati
Wilda Jean Baptiste
Julia Hidalgo
Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social Data
European Journal of Geography
Downscaling social data
upscaling social data
aggregation
disaggregation
mesh
spatial analysis
title Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social Data
title_full Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social Data
title_fullStr Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social Data
title_full_unstemmed Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social Data
title_short Statistical Reliability of the Modified Areal Weighted by Control Zones Method to Spatially Downscale Individual Social Data
title_sort statistical reliability of the modified areal weighted by control zones method to spatially downscale individual social data
topic Downscaling social data
upscaling social data
aggregation
disaggregation
mesh
spatial analysis
url https://eurogeojournal.eu/index.php/egj/article/view/824
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AT wildajeanbaptiste statisticalreliabilityofthemodifiedarealweightedbycontrolzonesmethodtospatiallydownscaleindividualsocialdata
AT juliahidalgo statisticalreliabilityofthemodifiedarealweightedbycontrolzonesmethodtospatiallydownscaleindividualsocialdata