The Index Of Distribution
Monthly movements in GVA for distribution industries
Please note: From March 2006 the Index of Distribution First Release and Index of Services Experimental Release were replaced by the Index of Services First Release. As of March 2007 the Index of Services has been classified as a mainstream National Statistic. The Index of Services First Release brings together in one place all monthly information on services and so contains the most up to date information on the output of the distribution sector.
The Index of Distribution (IoD) shows the monthly movements in gross value added for the distribution industries, which consist of the motor trades, the wholesale and commission trades and the retail trade (Standard Industrial Classification (SIC2003) section G).
Together these covered around 12 per cent of the UK economy - around 17 per cent of the service sector - in 2002.
Gross value added (GVA) is an important element in measuring the economy. GVA for the distribution industries is the difference between the value of a service provided (output), and the value of the goods and services used up in providing that service (intermediate consumption). The IoD show how this difference in value changes from month to month.
The IoD is estimated using the same data sources and National Accounts methodology as the quarterly estimate of distribution industries' gross value added within the output measure of Gross Domestic Product (GDP (O)). Ninety-three per cent of the source data are available on a monthly basis.
The development of a monthly IoD was the first step in the development programme for a monthly Index of Services (IoS). The IoD has now been re-categorised from 'experimental' to a mainstream statistic.
Before the IoD was introduced as a mainstream statistic ONS carried out a formal process of quality assurance involving methodologists and the statisticians responsible for developing the index. An evaluation report was written as part of this process. The evaluation report describes the IoD and provides an assessment of the overall quality of the index in May 2001, when it became a mainstream National Statistic.
An important part of the Index of Services development project is an industry-by-industry review of data sources and methods. Improvements to the sources and methods for motor trades and the wholesale trade were introduced in June 2002. For the motor trades, deflated turnover was introduced to replace vehicle registration data and fuel volume indicators. For wholesaling, deflated turnover of wholesalers has replaced indicators based on manufacturing turnover and retail sales.