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Data identification and collection

The base year for data collection was 2001, and the common reporting unit was tonnes. Ideally, all data used in the study would have been primary data reported in tonnes, by South West or national government sources. Unfortunately, not all data was available, and not all available data was in the required format. Consequently a proportion of data was calculated using assumptions and proxy factors, which are documented in the relevant sections below. Where 2001 data was not available, data was used from other years. Where data was not available in tonnes, conversion factors were applied.

The application of proxy measures

It was sometimes necessary to 'proxy' data from a number of sources to derive appropriate consumption figures for the South West. In most cases a number of proxying methods were considered, often the most appropriate one being adopted with the advice of the Advisory Group. Proxy measures applied to individual data sets are described in the relevant sections of the methodology below.

What is a proxy?

A proxy is a factor applied to available data to approximate the required level of data, for example applied to national data to scale it down to regional level. Proxy factors used can include economic data such as employment by sector or Gross Domestic Product (GDP), population, waste or expenditure data. A proxy is selected according to its relevance to the data being manipulated. Figures derived from a proxy will not be as accurate as primary data.

This section identifies the main data sources used for the resource flow analysis and discusses how data gaps were addressed and how results were derived.

Main data sources

South West-specific data was used wherever possible. Key data providers were identified, such as the South West Regional Assembly and Regional Development Agency, South West Observatory and Environment Agency. However, where regional data was unavailable, UK data was used to derive figures for the South West. Below is a brief description of the main data sources.

Direct energy

There was no single source of energy data for the South West. The Department of Trade & Industry (DTI) was the main source for electricity and gas consumption. Data on solid fuel and petroleum had to be proxied from UK data, also obtained from DTI. Other sources included the Office for National Statistics (ONS) and AEA Technology.

Materials

Data on UK imports, exports, production and consumption of agricultural materials was obtained from the Food and Agricultural Organisation (FAO). South West-specific agricultural information, provided by the Department for Environment, Food and Rural Affairs (DEFRA) was used to proxy this data to South West level. Minerals data was mostly South West-specific and obtained from the British Geological Survey (BGS).

Products

No South West-specific information on the volume of products consumed was available. ONS UK ProdCom data was proxied using South West-specific economic data supplied by the University of Plymouth.

Waste

Most waste data was South West-specific, and obtained from the Environment Agency and the South West Regional Technical Advisory Board (RTAB).

Hidden flows

Hidden flow data was obtained from the Wuppertal Institute's study on resource flows in the UK (Bringezu & Shutz, 2001).

Transport

Data on personal transport in the South West was mainly obtained from the Department for Transport and the National Travel Survey.

Water

Five of the main water companies based in the South West supplied information on the volume of water supplied, delivered and lost through leakage. Water UK supplied further information on water abstraction in the region by sector. All data was available at regional level.

Land use

Land use data was obtained from the Office for National Statistics Regional Trends 37 (2001a) report.

Emissions to air

Data on emissions to air was not available at regional level. UK data from the National Air Emissions Inventory Data Warehouse (NAEI) was proxied to the South West using economic data from the University of Plymouth. Levels of emissions by industrial sector were obtained from Biffa.

Due to differences in accessibility and quality of the data for each component, the methodology used to collect and calculate final consumption figures varied greatly. For this reason, components have been described in greater detail on the following pages.