100 years of the UK Census of Production

Paul Smith and Stephen Penneck

Office for National Statistics

Outline

• The origins of the Census of Production• Costs (and burdens)• Questionnaires and notes (and burdens)• Sampling (and burdens)• Coherence and consistency• Recent and future developments

Origins of the Census of Production (1)

• Census of Production Bill proposed by David Lloyd George, with opposition support from Joseph Chamberlain

• Driven by tariff policy information needs in Government

• UK latecomers by international standards– US had decennial Census from 1790

Origins of the Census of Production (2)

• Census of Production Act 1906 restricted topics– No wage/earnings data– Purchases of materials/fuel as one total only– Output breakdown limited to import/export list headings

• Questions decided by special advisory committees including representatives of industry

– Voluntary questions added

• First Census for 1907– All follow-up by post

1907 schedule (questionnaire)

Costs (and burdens) (1)

• 5-yearly pattern agreed before World War I• After the war, Censuses planned for

– 1920 (cancelled - expense)– 1922 (announced but shelved)– 1924

• Smallest businesses exempted – only to provide employment and classification

• gradually increasing cut-off, to ≤10• 5-yearly major surveys, intervening smaller

surveys, up to 1937-8

Costs (and burdens) (2)

• Reviews after World War II of– Census of Production– Census of Distribution

• General agreement on need for statistics• Reservations on timing, especially for Census of

Distribution• New legislation needed

Statistics of Trade Act (1947)

• Statistics of Trade Act 1947– Stipulates Census of Production each year– Provides statutory powers for collection of business

statistics– Obligation not to disclose information– Removed some restrictions on questions which could be

asked

Questions and notes (and burdens) (1)

• Already seen extent of notes in 1907• Considerable efforts to make questions ‘easy’

– Industry representatives– Some questions voluntary– Restrictions due to Census of Production Act

• Concepts adjusted to available information 1948– Sales collected instead of production– New questions piloted in 1946

Questions and notes (and burdens) (2)

• In 1951 experimental separation of questionnaire and notes

– Verdon Smith reported “improved appearance” and “economies”

– Continued for a long time– 1971 follow-up survey showed business preferred notes

with questions– Notes and questions merged again in 1990s!

Questionnaire technology

• Postal survey with postal follow-up in 1907• Business telephone numbers requested…

Questionnaire technology

• Postal survey with postal follow-up in 1907• Business telephone numbers requested 1949• Board of Trade add their telephone number to

questionnaire…

Questionnaire technology

• Postal survey with postal follow-up in 1907• Business telephone numbers requested 1949• Board of Trade add their telephone number to

questionnaire 1951• Telex number included…

Questionnaire technology

• Postal survey with postal follow-up in 1907• Business telephone numbers requested 1949• Board of Trade add their telephone number to

questionnaire 1951• Telex number included 1973 until mid-1990s• Fax number added to questionnaire…

Questionnaire technology

• Postal survey with postal follow-up in 1907• Business telephone numbers requested 1949• Board of Trade add their telephone number to

questionnaire 1951• Telex number included 1973 until mid-1990s• Fax number added to questionnaire 1987

Questionnaire technology

• Postal survey with postal follow-up in 1907• Business telephone numbers requested 1949• Board of Trade add their telephone number to

questionnaire 1951• Telex number included 1973 until mid-1990s• Fax number added to questionnaire 1987

• Scanning in Census of Employment 1993• More generally in business surveys c1995

Sampling (and burdens)

• Sampling introduced for 1952

“it was decided that sufficiently accurate estimates of the main aggregates required could probably be made…from a sample of establishments”

• Stratified design– All largest units (by employment)– Decreasing sampling fractions with decreasing

employment size– Same sampling fraction for given size in all industries– Businesses changing industry or starting trading since

previous Census (mostly) completely enumerated

Census of Production sample sizes 1930-97(thousands)

0

50

100

150

200

250

300

350

400

1930 1940 1950 1960 1970 1980 1990

Coherence and consistency

• Standard Industrial Classification (SIC48)• Integration with Europe

– UK joins European Economic Community 1973– harmonised European classification from 1992– Structural Business Statistics Regulation 1997

• Integration of surveys– Annual Business Inquiry merged Census of Production

with 8 other surveys

Principles (1)

• Retrenchment’ principle– Once a new collection introduced, retrenchment follows– Reduced coverage, costs, samples– Then expansion on quality or coverage grounds– Then another round of retrenchment

• Legislation principle– Difficult to start new collections, especially if legislation

needed– Corollaries:– Maximum use made of existing legislation– Maximum value required for new legislation

Principles (2)

• Continuous reduction of burden– Reduced participation (coverage, sampling)– Unit definition– Easier and fewer questions– Include ancillary activities

• Increasing use of automation– Gradual transition to electronic calculating machines

and computers– Embracing new technologies

Further developments

• Business Register and Employment Survey– Integrates register maintenance, employment variables

• Annual Business Survey– Redesigned annual collection across whole economy

(forthcoming)

Full paper on history of the UK Census of Production available on request

paul.smith@ons.gov.uk