1. Martin Szibalski Grid Data in Official Statistics of Europe A Survey about the Storage, Analysis and Publication of Census Data and Business Statistics Working Party Meeting "Geographical Information Systems for Statistics" from 15th to 16th March 2007

2. Agenda Aims and motivation Framework conditions Realisation Results
Summary
Perspective

3. Aims und motivation Census data Business statistics
Small-area grid data for internal and external analyses as well as for publications.
Business statistics
Data with coordinates of adresses for internal analyses.
Small-area grid data for publications and external analyses.
There are no practical experiences with statistical grid data. Therefore the official statistics in Germany would like to participate in the knowledge of the European neighbours by an survey.

4. Framework conditions I
Census data
The permanent storage together with adresses or with a reference to adresses is prohibited.
Adresses have to be deleted as soon as possible after a survey.
The spatial relation may be stored long-term only together with identifiers of lattice cells.
Business statistics
The permanent storage with adresses or with a reference to adresses is allowed.
The dissemination of the data together with adresses is prohibited.

5. Framework conditions II
In Germany it is necessary to establish a concept especially for the storage of the spatial relation of data concerning natural persons. A B C D E F G
Geographic Lattice
Data Coordinates
xxxx
yyyy
zzzz
34111, 52111
34222, 52222
34333, 52333
34444, 52444
Input data about persons
with coordinates
Data Lattice-ID
xxxx
yyyy
zzzz D2 D3
Output data with
identifiers of lattice cells

6. Realisation Survey from late October to early December 2006
Three batteries of questions broken down by census data and business statistics
Storage (only census data)
Analysis
Statistical confidentiality and dissemination
survey in 33 countries
18 feedbacks

7. Results

8. Results

9. Results

10. Disclosure control based on grid cells
Results
Census data
Min. grid size [m]
Disclosure control based on grid cells
Estonia
500
Less than 3 enumeration units
Finland *
250
- Less than 10 enumeration units
- Less than 2 residential buildings
Austria
125 / 250
From 125 m no limitation for absolute values
From 250 m limitations for subdivisions of attributes:
- less than 31 enumeration units (census data)
- less than 5 enumeration units (building or household attributes)
Norway
Less than 20 persons
Switzerland **
100
Less than 4 enumeration units
* Disclosure control only for sensitive attributes
** Disclosure control for a predefined variable set. Sensitive attributes will not be published.

11. Disclosure control based on grid cells
Results
Business statistics
Min. grid size [m]
Disclosure control based on grid cells
Estonia -
Finland
250
- Classification of personnel and turnover data
- Economic data of buying behaviour, income or consumer structure are protected like census data
Austria
125 / 250
- From 125 m no limitation for absolute values
- From 250 m no limitation for subdivisions of attributes
Norway
Less than 50 employees
Switzerland *
100
Less than 4 units
* Disclosure control for a predefined variable set. Sensitive attributes will not be published.

12. Summary
Permanent storage of adresses or adress references is allowed in countries which apply grid data. Germany has a unique position regarding its storage concept for census data.
In Europe statistical grid data are already frequently applied for analyses and publications espacially of population data.
The minimal grid sizes are very different.
Supressing grid cells is a common method to guarantee statistical confidentiality. Methods like overlap contigency or low-pass filtering are not applied.

13. Perspective Census grid data Business statistics grid data
The preparations for the next census (2010/11) are made. The legal dicisions concerning the use of the spatial reference of statistic data are not carried out at present.
Study about disaggregation of the population density with data of the national map agencies.
Business statistics grid data
Up to now there are only case scenarios and feasibility studies.
Methods to standardise adresses and to add geographic coordinates to these adresses are being developed at present.

14. Perspective Input data Output data Intended improvement
Official map agency data about residential areas and mixed zones
Inhabitants per municipality
Output data
Grid map with inhabitants per square kilometre
Intended improvement
Using of building adresses to define residential areas more exact