1. Data Capture Overview United Nations Statistics Division

2. Overview of Presentation
Definition of data capture
Methods of data capture:
Different Methods
Advantages and disadvantages
Issues to consider

3. What’s 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.

4. 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 4

5. 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 5

6. Advantages and Disadvantages of Keyboard Data Entry
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 6

7. 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 technology’s sake
Awareness of long lead times and technology infrastructure required for successful implementation of intelligent character recognition 7

8. 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 8

9. Advantages and Disadvantages of OMR
Improved data accuracy
Data capture faster than keyboard data entry
Equipment is relatively inexpensive
Relatively simple to install and run
A well-established technology that’s 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
Won’t capture textual responses 9

10. 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 10

11. 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 11

12. 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 12

13. 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 13

14. Advantages and Disadvantages of use of the PDA
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 14

15. 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 15

16. Advantages/Disadvantages of use of the Internet
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 16

17. 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 17

18. 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

19. Thank you