2016 Q2 DDI4 Development Draft - Comment and Review

This page provides coverage information for the DDI 4 Q2 2016 Development Draft Review plus links to the following:
  • Status report on each review document
  • Link to the review package
  • Link to the comment form
  • Link to the DDI 4 Drupal site
  • Link back to GENERAL REVIEW information and useful documents 

Special Instructions for this review:

Read this document BEFORE reviewing

Library Packages and Functional Views in Release

NEW Library Packages

Functional Views

Previous Library Packages

(Note these will have changed from 2015 Q1)

Collections Pattern

Agent Registry

Agents (revised using Collections Pattern)

Complex Process

Data Dictionary

Collections (renamed Collections Pattern)

Custom Metadata

Statistical Classification

Complex Data Types

Data Capture



Format Description

Core Process

Logical Data Description




Methodology Pattern


Process Pattern


Segment Location Specifications


Signification Pattern



Special Issues:

Modeling Team Open Issues:

·         Logical Data Description and Format Description have been placed in review as received from the Data Description working group without additional review by the Modeling Team.

·         The Methodology Pattern has been placed in review without a specific instantiated application. Methodology Pattern will be found only in the model, not in the XML Bindings as its classes are all abstract. Several instantiations of this pattern are anticipated in the upcoming special Codebook Release.

·         The interaction of Patterns (Collection, Process, Methodology, and Signification) is still under discussion. In particular, questions about combining Methodology and Process Patterns and the detail of content within classes belonging to a pattern are still being discussed. Comments and recommendations are welcome. As this is resolved the Modeling Team will provide a high level document providing a bird’s eye view of the conceptual framework of DDI, how the patterns interact, and how the patterns work together to express similar relationship patterns within different areas and applications of DDI.

·         Data Capture and Instrument View provide a design-time example of the Process pattern. We are working on a run-time example within the broader needs of a run time layer that provides actual run time binding, plus action logs, variation from design etc. This is part of the temporal perspectives talked about before (looking forward/design, execution/run, looking backward/what took place). This plays into the issue of capturing processing provenance as well as paradata during data capture operations.

·         The Service class in the Process Pattern will not talk about time. This will appear in the concrete class that realizes Service. There are three applications of time: Effective time (Availability), Historic time, and Expected Time. Look at estimatedDuration in the WorkflowService object.

·         Service does not relate correctly to Process Step. Leave as an open issue. Service needs a more complete review, but we should wait until we see how people implement it (regarding what properties they need.) There are also issues with the relationship between process step and service including the directionality of the relationship and the use of internal controlled vocabularies.

·         Should the Variable Cascade approach be replicated for forms of capture such as Questions? Is there a parallel in terms of comparison and reuse? If InstanceQuestion inherits from RepresentedQuestion it would solve the current issue of requiring the creation of both a RepresentedQuestion and an InstanceQuestion.

·         The Variable Cascade has been modified since the last development release and should be reviewed carefully.

Data Description (Logical Data Description, Format Description) Open Issues:

·         Only limited physical formats are currently described (Fixed Format and CSV). Development of other formats may include additional properties for PhysicalLayout, ValueMapping, and ValueAndConceptDescription.

·         Datum and its consequences are still being worked out. It expands the scope of DDI from the record into the actual datum (observation) and allows for support of datum specific paradata and viewpoints.  

Link to Review Package

Package based on Build #501



PDF of documentation is now available! Click on the link above. – Technical Committee


Follow the link "submit comment" to the issue tracking page for this release. Click on "CREATE" in the top banner and following the instructions.

IN THE SUMMERY LINE: Please enter the name of the document you are commenting on, a page number, and section and/or object name.

PLEASE submit a separate comment for each issue.

Please note your name and email at the beginning of the description


Link to Drupal development site

NOTE: Drupal is a development site so may reflect changes made AFTER the generation of the build used for the review. Some changes will be the result of review issue resolution, others the result of continued development work.


Library Package

In DDI 4, a group of classes within the Library related by a theme. The Class Library for DDI 4 encompasses the entire DDI 4.0 model, but without any specific schemas or vocabularies for Functional Views. Classes contain primitives and extended primitives and are the building blocks used to construct the Functional Views.

Functional View

 In DDI 4, a functional view identifies a set of classes that are needed to perform a specific task. It primarily consists of a set of references to specific versions of classes. Functional views are the method used to restrict the portions of the model that are used, and as such they function very much like DDI profiles in DDI 3.*.


Useful background documents:

Contact Information:

For questions regarding the review process please contact the Technical Committee list ddi-srg@icpsr.umich.edu or the Technical Committee Chair, Wendy Thomas wlt@umn.edu