§ Mr. Gould
asked the Secretary of State for Transport if in respect of the statistics kept and published by his Department, he will publish in the Official Report any changes since 1979 in (a) the statistical series which are published, including those which have been introduced and those which have been dropped, (b) the basis on which any elements in the statistics are estimated, calculated or presented, (c) the periods over which, and the dates on which the series are collected or published and (d) any other respects in the ways in which the statistics are collected, recorded, presented, evaluated, or published; and if he will explain the reasons for any such changes.
§ Mr. John Moore
Changes in the basis of compilation, presentation, and publication of statistical series are made from time to time in response to the Government's requirements for statistical information, changes in the administrative sytems on which some series are based, the development of new statistical techniques, and technological developments affecting the compilation and dessemination of statistical data. When such changes are made they are documented in the Department's annual statistical publication "Transport Statistics Great Britain", copies of which are in the Library.
The principal changes since 1979 have been:Bus and coach industry: the Transport Act 1980 and the Public Passenger Vehicles Act 1981 resulted in the redefinition of certain categories within the published statistics. The introduction of new returns for 1985–86 in anticipation of the provisions of the Transport Act 1985 has also involved some change in the published statistics.Domestic waterborne freight: new estimates of the volume of domestic waterborne freight traffic (that is freight traffic by coastal shipping and on rivers and other inland waterways) introduced in 1984.Heavy goods vehicles: development of the computer sytems at the Driver and Vehicle Licensing Centre allowed information on heavy goods vehicles derived from the vehicle licensing system to be used to compile statistics on HGVs and on road goods transport, in place of information from a register of vehicles on operators' licences. This change, which was made in the interests of economy and efficiency, produced some discontinuity in the statistical series and adjustments have had to be made to produce consistent series.Port Statistics: a "mode of appearance" classification was introduced in 1982 in place of the previous commodity classification which had become less relevant with the unitisation of cargo.Road traffic: series revised in 1984 due to the introduction of more sophisticated statistical techniques.Vehicle taxation: categories changed on 1 October 1982 which affected series for new vehicle registrations and vehicles currently licensed.