DLI Training

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DLI Training

• April 2004
• Kingston Ontario

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DDI

• What, Why, How?

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Data Documentation Initiative

• The Data Documentation Initiative is an
  international effort to establish a standard for
  technical documentation describing social science
  data
• http//www.icpsr.umich.edu/DDI/index.html

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Getting Used to Acronyms

• Youll see..

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DTD - Document Type Definition

• Consists of a Tag Library
• Tags have been developed by DDI
• A set of tags, when filled, are known as a
  codebook
• DDI intends to comply to Dublin Core

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Tags

• Tags present English language descriptions of XML
  (eXtensible Markup Language)
• Each tag can be optional or mandatory, repeatable
  or non-repeatable
• Set of tags for each section of DTD

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5 Sections of DTD (Document Type Definition)

• 1.0 Document Description
• 2.0 Study Description
• 3.0 Data File Description
• 4.0 Variables Description
• 5.0 Other Study Materials

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Document Description

• Bibliographic description of the DDI document
  itself, otherwise known as a marked-up codebook

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Study Description

• Describes Study or Survey
• Includes title, abstract, keywords, author,
  publisher, collection methods, etc.

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Data File Description

• Contains information describing the data file
• Includes file name, file type, case quantity,
  logical record length, total number of records,
  etc.

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Variables Description

• Describes each variable
• Includes variable label, values, value label,
  question, summary statistics, etc.

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Other Study Materials

• Includes documentation files in a variety of
  formats pdf, excel, word, etc.
• Includes codebooks, questionnaires, user guides,
  variability tables, etc.

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Choosing Tags

• http//www.icpsr.umich.edu/DDI/users/dtd/codedtd.h
  tml
• Select tags from each DTD section for template
• Each tag represents a searchable element
• Choose carefully definitions are provided
  on-line

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Codebook Template

• Over 300 tags to choose from
• DDI suggests starting with set of Recommended
  Elements

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Making Templates

• Pre-fill tags which are common to each dataset
  and save as template
• One template for Stats Canada surveys
• One template for ICPSR Surveys
• One generic to cover other sources

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Making Templates - example
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Marking up document

• Tags can be filled by a variety of methods
• Cut and paste or type in information
• Extract information using custom scripts, xml
  editors or custom software
• Follow tag descriptions carefully
• Establish guidelines

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Completed Codebook
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Displaying codebook

• XML is not a visual display language on the web
• Transform codebook using XSL/XSLT (extensible
  stylesheet language)
• Stylesheets control the output display
• Software required to read stylesheets, eg.
  Cocoon, Saxon

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Stylesheets what they look like
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Stylesheets

• Create your own
• Borrow from others examples available on DDI
  site
• Purchase proprietary software to do it for you
  example NESSTAR

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Final product

• ...........................

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Where to go from here..

• Borrow
• Share
• Collaborate
• Discuss
• Become involved.....

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Appendix Acronyms

• DDI Data Documentation Initiative
• DTD Document Type Definition
• XML eXtensible markup language
• XSL/XSLT extensible stylesheet language
• Template file containing a set of chosen tags
  to be used for each dataset
• Marked-up codebook all chosen tags are filled
  with survey information

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The end

• Carol Perry Ernie Boyko