1 / 24

2001 Output Areas Specification and Design Approaches in Data Collection

This document outlines the methodology for designing output areas (OAs) used for data collection, as presented in the RSS meeting of November 2000. It details the processes of specifying, demonstrating, and maintaining OAs, focusing on the separation of collection and output geographies for improved data utility. Key topics include the aggregation of postcodes, design constraints (contiguity, size, shape, and homogeneity), and the iterative process for zone design. The project aims to adapt to postcode changes and enhance data relevance using synthetic populations for testing.

hal
Télécharger la présentation

2001 Output Areas Specification and Design Approaches in Data Collection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 2001 output areas: specification, demonstration and maintenance David Martin, Abigail Nolan, Mark Tranmer RSS meeting: Nov 2000

  2. Overview • 2001 Output areas • Specification • Demonstration • Maintenance • Current developments RSS meeting: Nov 2000

  3. 2001 Output areas • 1991: EDs designed for data collection, but used for both data collection and output • 2001: separation of collection and output geographies - purpose-specific geographies • New output areas built from synthetic unit postcode polygons • Application of automated zone design (after Openshaw, 1977) RSS meeting: Nov 2000

  4. OA design (1) Initial random aggregation of postcodes into potential output areas RSS meeting: Nov 2000

  5. OA design (2) Choose one postcode at random as candidate for swapping into a different output area RSS meeting: Nov 2000

  6. OA design (3) Make the swap and evaluate the impact on the overall solution RSS meeting: Nov 2000

  7. OA design (4) If swap does not result in improvement, go back to the previous configuration RSS meeting: Nov 2000

  8. OA design (5) Choose another postcode at random as candidate for swapping into another output area RSS meeting: Nov 2000

  9. OA design (6) If the swap results in an overall improvement, keep it as part of the solution, and examine a new potential swap... RSS meeting: Nov 2000

  10. Specification Initial Random Aggregation of Building Blocks Iterative Recombination Design Constraints (Contiguity, Thresholds, Shape, Size, Homogeneity) 2001 Output Areas RSS meeting: Nov 2000

  11. Constraints (1) • Contiguity: output areas from adjacent postcodes (NB problem of stacks) • Thresholds: output areas above population thresholds (NB problem of sub-threshold parishes) • Shape: output areas should be as compact as possible • minimize perimeter2/area RSS meeting: Nov 2000

  12. Constraints (2) • Size: output areas should be as uniformly sized as possible - avoiding very large and very small populations minimize S(OApop-target)2 • Homogeneity: output areas should be as socially uniform as possible • maximize intra-area correlations RSS meeting: Nov 2000

  13. Intra-area correlation • Measures similarity of values within any area of interest (Holt et al., 1996). Higher correlation = greater homogeneity (theoretical maximum of d = 1.0) • Can be computed for a single category (eg. owner occupied) or for multi-category variables • Tenure and dwelling type evaluated RSS meeting: Nov 2000

  14. Zone design experiments • ONS postcode polygons for test areas • Populated with plausible synthetic populations by iterative sampling of SAR individuals (PCs structured by dwel. type) • Test OAs constructed using alternative combinations of design constraints: (OApop only; OApop+shape; OApop+homog; OApop+shape+homog) RSS meeting: Nov 2000

  15. Illustrative results… RSS meeting: Nov 2000

  16. Illustrative results… RSS meeting: Nov 2000

  17. Illustrative results… RSS meeting: Nov 2000

  18. Illustrative results… RSS meeting: Nov 2000

  19. Demonstration: website http://www.geog.soton.ac.uk/research/oa2001/ RSS meeting: Nov 2000

  20. OA Demonstrator • Experimental results for Kerrier (rural-villages), Cardiff (urban-suburban) and Manchester (metropolitan) • ONS prototype postcode polygon set • Threshold population 100, targets of 150, 250 • Combinations of population, shape and intra-area correlation controls • PDF, CSV and Shape file samples online RSS meeting: Nov 2000

  21. Demonstrator data RSS meeting: Nov 2000

  22. Maintenance • Continual postcode change • Recoded and analysed postcode change in Manchester test area • Most changes: relabelling or splitting • Developments during course of project: • ONS to maintain postcode to OA directory • OS to create postcode boundary set RSS meeting: Nov 2000

  23. Current developments • ONS create own synthetic postcode polygons for input to OA design • NISRA digitize postcode polygons, then input to ONS OA design • Homogeneity – for consultation and final decision. NB different considerations in NI • GROS already have postcode polygons, but different OA design procedure (smaller OAs) RSS meeting: Nov 2000

  24. For further information • Project website: http://www.geog.soton.ac.uk/research/oa2001/ • For this presentation, follow: • Publications and resources • For demonstrator datasets, follow: • OA demonstrator RSS meeting: Nov 2000

More Related