Scottish Neighbourhood Statistics Data Zones Background Information

Scottish Neighbourhood Statistics Data Zones Background Information

3 Data zone Index Guidance

The Data zone Index is made up of four components:

• SNS Postcode Index - the postcode look-up file which shows the geographic relationships between postcodes and census output areas, data zones and local authorities.
• SNS Census Output Area Index - the look-up showing the relationships between 2001 census output areas and data zones and local authorities.
• SNS Data zone Index - the look-up showing the relationships between data zones and local authorities.
• Names and codes - standard names and codes for geographies supported in Scottish Neighbourhood Statistics.

Data sources

The following data sources have been used to produce the data zone index

GROS Postcode Index 2003v2
GROS 2001 Census OA INDEX
SNS Data zones

(A) SNS Postcode Index (snspc03bp)

The SNS Postcode Index is the postcode look-up file which shows the geographic relationships between postcodes and some of the geographies supported in Scottish Neighbourhood Statistics. The SNS Postcode Index differs from the publicly available GROS postcode index because within SNS relationships are determined via 2001 Census output areas. This means that the postcode relationships are inherited from the census output area rather than being determined by identifying which area the actual postcode unit falls in.

The SNS Postcode Index is created by combining (i) the postcode unit to census output area relationships from the 2003v2 GROS Postcode Index, with (ii) the 2001 Census output area to SNS Geographies from the 2001 Census OA Index; and (iii) SNS data zones.

Fields on the index

The index includes the following relationships and fields:

Postcode unit (outward code)	(postcod1)
Postcode unit (inward code)	(postcod2)
Postcode unit to 2001 Census output area	(outcd01)
Postcode unit to data zone	(data_zone)
Postcode unit to local authority	(council_area)
Date of introduction	(dateintr)
Date of deletion	(datedele)
Large user identifier	(splitare)

Current and deleted postcodes

The SNS Postcode Index includes both current and deleted postcodes.

Large user postcodes

Large user postcodes are those postcodes which receive more than around 50 mail items per day. The SNS Postcode Index includes large user postcodes and these are identified through the large user identifier field (splitare). The following codes are used in splitare:

A=split postcode

Z=large postcode matched with one of the split areas for a small postcode;
L =large postcode matched with small postcode - no split areas;

Split postcodes

A very small number of postcodes straddle local authority boundaries. When this happens GROS (who maintain boundaries for postcodes) split the postcode in to two or more parts and label these A, B, C etc. Split postcodes have been stripped out of the SNS Postcode Index and only the largest part (in terms of households) is included in the index.

(B) SNS Census Output Area Index (snscoa03bp)

SNS Census Output Area Index - the look-up showing the relationships between 2001 census output areas and some of the SNS geographies.

Fields on the index

Census output area	(outcd01)
Census output area to data zone	(data_zone)
Census output area to local authority	(council_area)

(C) SNS Data zone Index (snsdz03bp)

The SNS Data zone Index provides some key information about data zones including their relationships to local authorities.

Data zone	(data_zone)
Data zone area measurement (hectare)	(dzarea)
Data zone to local authority	(council_area)

Data zones have been coded sequentially from 1 through 6505, using the following structure:

S01000001

…

S01006505

S - represents Scotland

01 - represents the geography i.e. 'data zone'

001234 - represents the data zone number

(D) SNS Names and codes

SNS Names and codes sets out the names and codes to be used for local authorities, census area statistic wards, Scottish Parliamentary Constituencies and health boards within SNS.