Copyright 2010, The World Bank Group. All Rights Reserved. PROCESSING, Part 1 Data capture, editing,...
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Transcript of Copyright 2010, The World Bank Group. All Rights Reserved. PROCESSING, Part 1 Data capture, editing,...
Copyright 2010, The World Bank Group. All Rights Reserved.
PROCESSING, Part 1
Data capture, editing, imputation and tabulation
Quality assurance for census
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Copyright 2010, The World Bank Group. All Rights Reserved.
COMPONENTS OF PROCESSING
Data CaptureEditingImputationTabulation
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Copyright 2010, The World Bank Group. All Rights Reserved.
DATA CAPTURE
Key EntryScanningDirect Entry
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Copyright 2010, The World Bank Group. All Rights Reserved.
KEY ENTRY
Key entry as a data capture techniques has advantages and disadvantages:
Pro• Relatively inexpensive• Skills readily available• Employment
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Copyright 2010, The World Bank Group. All Rights Reserved.
KEY ENTRY (cont’d)
Con• Time consuming• Requires many workstations• Error prone
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Copyright 2010, The World Bank Group. All Rights Reserved.
SCANNING
Scanning is a process similar to photocopying, but the current technology has advanced far beyond simple photocopying.
There are three levels of scanning:1. OMR: Optical Mark Recognition2. OCR: Optical Character Recognition3. ICR: Intelligent Character Recognition
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Copyright 2010, The World Bank Group. All Rights Reserved.
SCANNING (cont’d)
Pro• Fast processing
• Reliable
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Copyright 2010, The World Bank Group. All Rights Reserved.
Con• Expensive upfront costs for equipment ,
software, & training• Very precise requirements for paper,
printing and processing
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SCANNING (cont’d)
Copyright 2010, The World Bank Group. All Rights Reserved.
DIRECT ENTRY
• Most Recent Innovations
• Enumerators use hand-held computers,
or where internet is common
• Self enumeration through the internet
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Copyright 2010, The World Bank Group. All Rights Reserved.
DIRECT ENTRY
Pro• More efficient– Saves a step (immediate data capture)
• Improves data quality– Editing at respondent level– Timeliness
• Reduces some costs– Printing questionnaires
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Copyright 2010, The World Bank Group. All Rights Reserved.
DIRECT ENTRY
Con• Requires better trained enumerators• Riskier– Hardware failure– PDA loss– Requires electricity
• Expensive
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Copyright 2010, The World Bank Group. All Rights Reserved.
EDITING
The Editing Process• Identifies errors• Identifies non-response• Identifies logical inconsistencies
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Copyright 2010, The World Bank Group. All Rights Reserved.
DEALING WITH ERRORS
• Replacement (Imputation)
• Weighting
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Copyright 2010, The World Bank Group. All Rights Reserved.
IMPUTATION
Two classes of imputation
• Deterministic
• Stochastic
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Copyright 2010, The World Bank Group. All Rights Reserved.
DETERMINISTIC IMPUTATION
• Will yield the same answer each time– Missing data may be calculable from other values
- e.g. Citizenship can be calculated from Place of Birth
– Missing data is imputed by a sequential donor technique or any other method that will yield identical results
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Copyright 2010, The World Bank Group. All Rights Reserved.
DETERMINISTIC IMPUTATION
• Six main types– Deductive or Logical– Mean Value– Ratio/Regression– Sequential Hot Deck– Sequential Cold Deck– Nearest-Neighbor
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Copyright 2010, The World Bank Group. All Rights Reserved.
STOCHASTIC IMPUTATION
• Can yield different results if the process is rerun– Use of a random donor or other randomized
approach– Use of randomized residuals to create realistic
data
• Most deterministic methods have a stochastic counterpart
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Copyright 2010, The World Bank Group. All Rights Reserved.
IMPUTATIONWhich inconsistency to change?• The general rule is to change as few values as
possible• Which values to impute?– For a 10 year old married university graduate, do
we change the age or the education and marital status?
– changing only the age can make the record consistent, therefore change age
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Copyright 2010, The World Bank Group. All Rights Reserved.
VALIDATION
After imputation data are consistent.May or may not be correctValidation is the final step before certification
and release
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Copyright 2010, The World Bank Group. All Rights Reserved.
VALIDATION
May be subject to bias: • Design• Training• Enumerator• Respondent• Processing
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Copyright 2010, The World Bank Group. All Rights Reserved.
CERTIFICATION
Final step before data release
NSO’s expression of confidence in the data
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