§ Mr. Gouldasked the Secretary of State for Trade if he will circulate in the Official Report a table showing the percentage increase in the United Kingdom export price of manufactures in each statistical base-weighted period since 1949 for periods in which any two series overlap, and an explanation for the differences, if any, in the results.
§ Mr. Meacher:Following is the information:
PERCENTAGE CHANGES IN THE UNITED KINGDOM EXPORT UNIT VALUE INDEX OF MANUFACTURERS Period of Comparison and Original Series Base Year percent.Change 1949 Ql to 1950 Q4 1949 †9 1950 Ql to 1951 Q4 1950 †31 1951 Ql to 1952 Q4 1951 †13 1952 Ql to 1953 Q4 1952 _5 1953 Ql to 1954 Q4 1953 _2 1961 Ql to 1962 Q4 1954 †2½ 1970 Ql to 1972 Q4 1961 †24 1975 Ql to 1977 Q4 1970 †61 Subsequent Series Base Year percent.Change 1949 Ql to 1950 Q4 1950 †9 1950 Ql to 1951 Q4 1951 †29 1951 Ql to 1952 Q4 1952 †14 1952 Ql to 1953 Q4 1953 _5½ 1953 Ql to 1954 Q4 1954 _2 1961 Ql to 1962 Q4 1961 †2½ 1970 Ql to 1972 Q4 1970 †16 1975 Ql to 1977 Q4 1975 †56 Note to Table
The figures in the table compare, for appropriate overlap periods, the percentage change in the unit value index series compiled according to the pattern of trade in successive base years. The overlap period has been defined as spanning the first and last quarters for which both series were compiled on a strictly comparable basis. Thus, for example, for the 1970-based series and the existing 1975-based series, which was introduced in January 1978, the overlap period runs from Q1 1975 to Q4 1977.
In each of the above comparisons, the difference in the growth rates for the two series will reflect a number of factors, which may work in different directions. In particular, the series will have been derived from different weighting patterns reflecting the composition of exports of manufactures in the two base years. Further, improvements in methodology 22W and in the quality of the sample will have been made at successive rebasings.
In the years up to 1954, rebasing was undertaken annually and was carried back for the previous year. Differences in this period are generally small.
In addition to the factors given above, for the 1961-based and 1975-based series, differences may have resulted from the introduction with these series of new trade classifications, while towards the end of the life of the 1961-based and 1970-based series changes in the tariff headings may have been a contributory factor.
It is not readily possible to quantify the effect of each of these changes separately.