Data Capture Overview

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• Data Capture Overview
• United Nations Statistics Division

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Overview of Presentation

• Definition of data capture
• Methods of data capture
• Different Methods
• Advantages and disadvantages
• Issues to consider

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Whats Data Capture?

• Data capture is the system used to convert the
  information obtained in the census to a format
  that can be interpreted by a computer.
• Source United Nations Principles and
  Recommendations for Population and Housing
  Censuses, Rev. 2, p.68.

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Data Capture Methods

• Keyboard data entry
• Optical mark recognition/reading (OMR)
• Optical character recognition/intelligent
  character recognition (OCR/ICR)
• Personal digital assistant (PDA)
• Internet
• Advantages/disadvantages/costs/impacts at both
  data capture and later stages
• Combination of more than one of the above methods

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Keyboard Data Entry

• Response codes from census form are manually
  entered into computers
• Sophisticated version involves computer assisted
  key entry where operator selects a response from
  options displayed on the screen
• Use of method based on time and cost
  considerations, and feasibility to implement more
  sophisticated technology
• Method also used to process textual responses
  into classification categories

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Advantages and Disadvantages of Keyboard Data
Entry

• Advantages
• Method requires simple software systems and
  low-end computing hardware
• Less costly (depending on the costs of manpower)
• There will be a large number of PCs available for
  other uses after census

• Disadvantages
• Requires more staff
• Task takes much longer time to complete than with
  automated data entry
• Potential for errors during data entry
• Standardization of operations is difficult as
  performance may be individually dependant

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Data Capture Technologies

• Imaging and intelligent character recognition
  offer great potential and benefits for data
  capture
• Use of technology for data capture should be to
  enhance effective and efficient data capture and
  not for technologys sake
• Awareness of long lead times and technology
  infrastructure required for successful
  implementation of intelligent character
  recognition

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Optical Mark Recognition/Reading (OMR)

• OMR is a form-scanning method whereby responses
  are read into a computer without a keyboard
• OMR technology reads responses to tick-box type
  questions on specially designed paper
• Only presence or absence of a mark is detected by
  the machine
• The scanned responses are transformed into codes
• Handwritten responses must be manually entered or
  coded using computer-assisted methods

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Advantages and Disadvantages of OMR

• Advantages
• Improved data accuracy
• Data capture faster than keyboard data entry
• Equipment is relatively inexpensive
• Relatively simple to install and run
• A well-established technology thats been used in
  many countries

• Disadvantages
• Restrictions as to form design
• Restrictions on type of paper and ink
• Precision required in printing process/cutting of
  sheets
• Response boxes should be correctly marked with
  appropriate pen or pencil
• Wont capture textual responses

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Optical Character Recognition (OCR)/ Intelligent
Character Recognition (ICR)

• OCR and ICR combine scanning and character
  recognition technology to scan the whole form and
  interpret the responses
• OCR technology recognizes machine-printed
  characters only
• ICR technology reads both machine-printed and
  hand-written responses in specific locations of
  the page and transforms the responses into codes
• For OCR, handwritten responses must be manually
  entered or coded using computer-assisted methods

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Advantages of OCR/ICR

• Form design is not as stringent as for OMR
• Processing time can be reduced due to automated
  nature of the process
• Allow for digital filing of questionnaires
  resulting in efficiency of storage and retrieval
  of questionnaires for future use
• Some handwritten responses can be automatically
  coded thereby improving data quality

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Disadvantages of OCR/ICR

• Higher costs of equipment (sophisticated
  hardware/software required)
• High calibre IT staff required to support the
  system
• Handwriting on census forms be as close as
  possible to the model handwriting to avoid
  recognition error
• Possibility for error during character
  substitution which would affect data quality
• Tuning of recognition engine to accurately
  recognize characters is critical with trade-off
  between quality and cost

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Personal Digital Assistant (PDA)

• Contents of the census form are stored onto the
  PDA so that the questions appear sequentially on
  the screen
• Data are entered into a hand-held computer
  instead of onto a paper census form
• Data are then electronically transmitted to an
  NSO database for further processing

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Advantages and Disadvantages of use of the PDA

• Advantages
• Instant data capturing at the point of
  collection, reducing manual input errors
• Immediate data validation, reducing
  re-verifications at later stage
• Time effective with real time logical validation
  rules, reducing logical errors
• Faster processing of census information leading
  to timely availability of results

• Disadvantages
• Setting up of process may take a long time as it
  requires extensive testing
• Requires that enumerators have ability to use the
  device which may require administering a test
• Requires intensive training of enumerators on use
  of device (training is more complicated)
• Need to recharge the battery which could run out
  during enumeration
• Possibility of equipment failure

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Internet-based Data Collection

• Use of the Internet for census data collection is
  growing
• However, the method is always complementary to
  other more established methods
• Like with PDAs, the on-line form is not a
  downloadable version of the paper form
• Use of this method requires a password in order
  to access and fill in the form
• Development of the internet system for data
  collection is generally outsourced for lack of
  in-house expertise

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Advantages/Disadvantages of use of the Internet

• Advantages
• Reduced resources necessary for form handling and
  data capture
• Better opportunity to enumerate difficult to
  reach and to enumerate geographic area and
  population groups
• Automatic filtering of irrelevant questions
• Better quality data due to in-built interactive
  verification mechanism
• Faster availability of census results through
  simplified data entry and editing

• Disadvantages
• Requires that respondents have a computer with
  Internet access
• Management of responses can be problematic, e.g.,
  that households have responded once and only once
• Requires high security system to ensure safe
  transfer of data
• Need to build parallel processing system as not
  everyone will use the Internet
• Requires mechanism to check for omitted and
  duplicate submissions
• Is costly and requires a lot of resources for
  setting up and adequately test the system

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Issues to Consider in Choosing a Method

• Method to use is dependant on national
  circumstances
• Choice of method should be part of the overall
  strategic objective of the census in terms of
  timeliness, accuracy and cost
• Choice of processing system and technology to use
  need to be established early in census cycle
• Enough time is required to test and implement the
  system
• When imaging technology is used for data capture,
  extensive testing is required well in advance of
  the census
• Possibility to outsource when the required
  expertise is not available in-house

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Issues to consider (cont.)

• Extensive testing of the system is also critical
  when data collection is either by PDA or via the
  Internet
• Design and paper quality of census form should be
  linked to method of data capture
• When imaging technology is to be used, adequate
  training of enumerators on how to properly fill
  in the forms is crucial

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• Thank you