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Occupational coding in practice: from the 1981 to 2001 Census of Population Tessa Staples June 2004. ( ons). Census Occupational Coding 1981 to 2001. Transition 1981 Manual or Clerical coding - 10% Sample 1991 Computer assisted coding - 10% sample 2001 Automated coding
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Occupational coding in practice: from the 1981 to 2001 Census of Population Tessa Staples June 2004 (ons)
Census Occupational Coding 1981 to 2001 Transition 1981 Manual or Clerical coding - 10% Sample 1991 Computer assisted coding - 10% sample 2001 Automated coding (automatic coding and interactive coding) - No sample processing
Census Occupational Coding 1981 to 2001 Census processing 1981 Managed in-house - Titchfield and Bootle offices 1991 Managed in-house - Titchfield and Hillington offices 2001 Contracted to Lockheed Martin - Widnes office
Census Occupational Coding 1981 to 2001 Classifications and coding frames 1981 Classification of Occupations 1980 351 operational codes 1991Standard Occupational Classification (1990) 480 component codes 2001 Standard Occupational Classification 2000 353 unit group codes
Census Occupational Coding 1981 to 2001 Information needed by the coding index CO80 SOC SOC 1990 2000 Job title Job description Industry of employer Professional qualifications Employee/Self-employed Major organisation
Census Occupational Coding 1981 to 2001 Occupation coding index Principles and layout style were devised for efficient clerical coding • Simple look-up • Quicker coding • Greater coding consistency
Census Occupational Coding 1981 to 2001 Occupation coding index Using indexing words Warehouse manager Warehouse salesman Warehouse cleaner
Census Occupational Coding 1981 to 2001 Occupation coding index Using indexing words Warehouse manager = 1162 Warehouse salesman = 7111 Warehouse cleaner = 9233
Census Occupational Coding 1981 to 2001 Know your onions - at the check-out “Why can’t I find onion in the list?”
Census Occupational Coding 1981 to 2001 Know your onions - at the check-out Because listed as ‘Brown onion’
Census Occupational Coding 1981 to 2001 Occupation coding index Reverse word order In response - Pest control inspector In index - Inspector, control, pest • Brings together variations on the indexing word in one place • Enables use of ‘default’ entries
Census Occupational Coding 1981 to 2001 Occupation coding index Qualifiers to indexing words • Occupation qualifiers • Additional qualifiers • Industry qualifiers
Census Occupational Coding 1981 to 2001 Occupation coding index List for Gateman 8219 Gateman, bridge 8219 Gateman, dock 8219 Gateman, flood 8219 Gateman, lock 8216 Gateman (coal mine) 8219 Gateman (docks) 9249 Gateman (entertainment) 8216 Gateman (railways) 8219 Gateman (waterways) 9241 Gateman
Census Occupational Coding 1981 to 2001 Occupation coding index List for Chain makers 5495 Maker, chain (metal, precious) 8129 Maker, chain (metal) 5211 Maker, chain (metal trades, forging) 8129 Maker, chain (metal trades) 8113 Maker, chain (textile mfr)
Census Occupational Coding 1981 to 2001 Occupation coding index Power of the default entries (from use of index in 1991 Census) Cleaner 35.9% Cleaner, school 8.0% Cleaner, office 6.4% Cleaner, window 6.0%
Census Occupational Coding 1981 to 2001 Organisation - 1981 and 1991 Censuses Headquarters • Instructions, coding indexes (amendments), training exercises • Analysis of coding queries • Independent quality control - ‘blind’ checking • Audit inspection - 1991 only Teams coding occupation and employment status • Supervisors - answered coding queries • Coders • Query writers - 1991 only • Query resolvers - 1991 only
Census Occupational Coding 1981 to 2001 Organisation - 2001Census Headquarters - ONS • Guidance, master copy of coding index (amendments), tuning data (thousands of coded job titles in natural word order) • ‘Second stop’ query resolvers • Sight checking Teams coding occupation (some cross-topic training) • Supervisors • Frontline coders • Expert coders - ‘First stop’ query resolvers
Census Occupational Coding 1981 to 2001 1981 Census coding Coders used • Census specific coding instructions • also on an A3 sized flowchart • Modified Occupation Coding Index • notes on coding • most industry qualifiers converted to Census industry codes
Census Occupational Coding 1981 to 2001 1981 Census Modified Occupation Coding Index Gateman; bridge … … … … … 338 dock … … … … … 338 flood … … … … … 338 lock … … … … … 338 Gateman- … … … … … 140 503 … … … … … 321 742 … … … … … 321 746, 749 - waterways .. … … … 338 750 … … … … ... 338 801,802 … … … … 165
Census Occupational Coding 1981 to 2001 1991 Census coding Coders used • Census specific coding instructions • also on an A3 sized flowchart • ‘Computer Assisted Census Occupation Coding’ (CACOC) • displayed the modified occupation coding index on the screen of a stand-alone PC
Census Occupational Coding 1981 to 2001 1991 Census coding CACOC • developed by Census IT staff at General Register Office for Scotland (GROS) • similar to the Australian coding tool, ASCO • not to reduce the number of coders but achieve better coding consistency (?)
Census Occupational Coding 1981 to 2001 1991 Census - CACOC OCCUPATION TITLE:GATEMAN Gateman bridge dock flood lock 503 742 746,749 waterways 750 801,802 Except above
Census Occupational Coding 1981 to 2001 1991 Census - CACOC OCCUPATION TITLE:GATEMAN Gateman bridge dock flood lock 503 742 746,749 waterways 750 801,802 Except above 420
Census Occupational Coding 1981 to 2001 2001 Census • Capture and coding contracted to Lockheed Martin • LM chose ACTR (Automated Coding by Text Recognition) as the coding tool • ONS’s Census staff specified contract and provided much support to LM • Processing operation subcontractedto ICL • ICL’s Knowledge Pool produced the training material
Census Occupational Coding 1981 to 2001 Qualifications indicator box 2001 Census - Occupation coding screen Image of census form Job title on record Enter text for search Search Code Unit group title Choice list Industry code SIC group title Accept Not codeable To expert
Census Occupational Coding 1981 to 2001 2001 Census - Occupation Coding Job title on record = Cellzzman Industry code on record = 51 Text entered by coder = CELLARMAN wine SOCSICText 9149 159 Cellarman <wine mfr.> 9149 51 Cellarman <wine merchants> 8111 159 Cellarman 9225 551 Cellarman . 9225 BAR CELLARMAN 9225 BAR/CELLAR SUPERVISOR 9225 BAR STAFF/CELLARPERSON
Census Occupational Coding 1981 to 2001 Number of occupation coding queries 1981 - 37,000 Apparently too few 1991 - 175,000 (in 54 metal trays on three trolleys) 2001 - 33,000 As sent to ONS Revising the coding index during processing1981 1991 2001 Number of times the index was revised 6 4 10 Total number of changes 131 393 311
Census Occupational Coding 1981 to 2001 Independent quality control reported 1981 Census - 4.9% error rate 1991 Census - 5.5% error rate 2001 Census • Contract specified as acceptable 12.0% error rate • Lockheed Martin reported 8.9% error rate • ONS assessed from sight checking 10.96% error rate • Automatic coding throughput 72.2%