DTD Version History

Prior to Initial Public Release


Includes PFS-authored sections only.


19.4.96 Incorporates NANMV-authored sections.


22.4.96 Addition of ATTLISTs to NANMV sections and general cleanup, in progress. Leading to:


23.4.96 First version that pretends to completeness.


21.5.96 Incorporates 3/96-4/96 changes in descriptions.


29.5.96 Incorporates 5/96 changes in descriptions except header.


7.6.96 Minor repairs.


11.7.96 Further minor repairs occasioned by conversion to parameter-entity file (teicb1.dtd, version 1.5).


Modified by Daniel Pitti, UC Berkeley, Library. Provided value "PCDATA" for TEI parameter entities to make it possible to parse and test the DTD. Parsed with NSGMLS and Near&Far


Modified by Jan Nielsen (JN), Danish Data Archives. Modifications in several places to produce a version compliant with the W3C XML version 1.0 proposal of December 8th 1997. Parsed and tested with Microsofts Java parser MSXML (ver. 1.0.8). The XML 1.0 specification used is available at http://www.w3.org/TR/PR-xml-971208.

  • and-connectors have been replaced by sequence-connectors. The order of elements is unchanged.

  • tag-minimization parameters have been removed.

  • Parameter entity references without semicolons have been fixed.

  • Name groups are avoided by expansion of element and attribute declarations.

  • Element inclusions have been discarded.

  • Attribute default values have been quoted.

  • NUMBER data type have been replaced by CDATA in attribute values.


7/1/98 Modified by Jerome McDonough, U.C. Berkeley Library Systems Office. Extensive revisions to both structure and content of DTD, including:

  • making Study Level Title only required element

  • Adding notes on mapping from DDI DTD to Dublin Core


9/15/98 Modified by J. McDonough, U.C. Berkeley Library Systems Office. Modifications include:

  • separate declarations of citation formats for docDscr and stdyDscr portions of document combined

  • an XML version of the Exchange Table Model version of CALS Tables (from OASIS) incorporated in DTD.


12/14/98 Modified by J. McDonough, U.C. Berkeley Library Systems Office. Modifications include:

  • origFundAg and origGrantNo elements added to producer statement in citation in the Document Description, to allow people to encode information on funding for previous versions of the codebook.

  • Affiliation attribute added to Distributor

  • deposReq element added to Data Use statement for information on depository requirements on papers generated from data

  • minor alterations made to attrib. vocabulary for fileStrc

  • vargrp attribute on var element removed as redundant; use var attribute on vargrp element to encode vargrp to var relationships

  • cardNo attribute added to File Location element

  • default on interval attrib on var element changed to 'discrete'

  • catStat element made repeatable

  • controlled vocab of (start|end|single) established or date event attributes

  • order of origProducer and software elements in production statement in citation reversed

  • DocuNo element in citation has name changed to IDNo

  • date of deposit element made repeatable to match depositor

  • recGrp and subsidiary elements reinstated beneath the fileStrc element


1/4/99 Modified by J. McDonough, U.C. Berkeley Library Systems Office. Changes include:

  • new element, srcDoc, added to document description section for encoding bibliographic cite for original codebook from which electronic version is derived

  • Separate copyright element in doc. desc. replaced by new copyright element in producer section of citation's content model

  • catStat now includes 'table' in its content model

  • 'for' attribute removed from contact element

  • abstInfo eliminated. abstract date element made attribute of abstract.

  • Missing and missing type attribs. added to Category group

  • new date attributes

  • Funding Agency and Grant No elements added to Production statement for citation element

  • new range elements for valrng, invalrng

  • sdatrefs added to qstn element


Orig[Producer|GrantNo|fundAg] removed from citation element, and duplicate GrantNo and fundAg removed as well. New role attribute added to grantNo and fundAg.


copyright element removed as redundant.


Definitions of elements modified to reflect preliminary tag library definitions.


Implementation of suggested changes from ICPSR OR meeting, including:

  • Data collector dropped from all citation elements and moved to 2.3.1

  • MARCURI attributed added to all citation elements

  • New holdings element added to all citations

  • Documentation source made repeatable

  • dataDist element renamed to distrbtr

  • New format attrib. added to biblCit to specify citation format used

  • URI attrib. added to Series Statement

  • citation elements added to all sections of 2.5

  • New vocab attribute added to keywords element

  • New concept subelement added to var element

  • URI attribute added to Distributor element to enable online contact of download/ordering service

  • Date attrib. added to software element

  • e-mail and uri attribs. added to contact element

  • xml:lang attrib. changed to NMTOKEN

  • new pubrefs attrib. added to file/var/varGrp

  • all URL attribs. changed to URI

  • New subelements respUnit & anlysUnit added to var

  • New subelement derivation added to var

  • Range element recast per NESSTAR recommendation

  • New element stdCatgry under var

  • catgry attrib. added to catgryGrp to allow nesting

  • vendor attrib. added to var and to labl

  • varGrp attrib added to varGrp element to allow nesting of variable groups

  • recGrp attrib. added to recGrp element

  • keyvar attrib on recGrp made IDREFS

  • URI attribute added to fileDscr

  • sumDscr and dataColl made repeatable

  • country attrib added to catgry element

  • new major section added for access conditions, with access-related elements from study description and elsewhere merged in. Access attrib added to var, varGrp, fileDscr and stdyDscr.


Includes a variety of changes, including several revisions to changes made as a result of the ICPSR OR Meeting. Experimental additions include:

  • A new Link element, available in leaf elements of the DTD, to express arbitrary links to other elements within the codebook.

  • A new section of the codebook for local extensions, which may be defined in a new attached file called codebook.ext.ent

  • section 5 of the codebook, for describing access conditions, has been eliminated, with elements from that section reinstated in section 2.4. Link attributes for pointing to access information have been preserved.

  • controlled vocabulary added to varGrp type attrib.

  • variable format attribute changed to new varFormat element with new attributes to allow more specific description of data storage for variable

  • rectype attribute added to var element

  • cardNo attribute on location renamed to RecSegNo, a new fileid attrib. added, and location made repeatable



  • eliminates local extension mechanism

  • category groups are now nestable

Public Release



  • no additional changes


MINOR MODIFICATIONS by Perry Roland, University of Virginia, 1/11/2001

  • added notes element to content models of stdyDscr and dataDscr elements

  • made notes element optional & repeatable in each content model where it occurs

  • added agency attribute to cleanOps element

  • added cycle attribute to timePrd and collDate elements

  • added sdatrefs attribute to catgry element

  • added sdatrefs attribute to notes element

  • made dataChck element optional & repeatable in content model of fileTxt element

  • added catStat element to content model of catgryGrp element

  • edited code examples illustrating use of level attribute at A.1, Other Material: to reflect correct attribute values

  • added version attribute to codeBook element to facilitate machine processing


MODIFICATIONS by Perry Roland, University of Virginia, 8/8/2001 following DDI Comm. meeting in Wash., D.C. 6/29/2001

  • added callno, label, and type attributes to setAvail element (2.4.1)

  • added callno, label, type, and media attributes to relMat element (2.5.1)

  • added concept element already defined in 4.3.21 to content model of varGrp element (4.1).

  • added wgtd, wgt-var and weight attributes to catStat element (

  • added media attribute to holdings element (A.6.8)

  • added level attribute to IDNo element

  • added sdatrefs attribute to qstnLit (, txt (A.3), and catStat ( elements.

  • altered content model of the following elements: universe (, anlyUnit (, anlysUnit (4.3.7), nation (, geogCover (, geogUnit (, dataKind (, timeMeth (, sampProc (, collMode (, srcOrig (, resInstru (, and varGrp (4.1)

  • created new ExtLink (external link) element (A.12) to allow encoding of links to resources outside the codebook

  • modified content model of fileDscr (3.0), added locMap (3.3), and modified dataDscr (4.0) per http://www.socsci.umn.edu/~wlt/ddi/AGG/JUNE_MTG/AGG-final-schema.doc


MODIFICATIONS by Wendy Thomas, University of Minnesota, 2/20/2002 following DDI Comm. meeting in Wash., D.C. 1/15/2002

  • renumbered locMap 3.3 to 3.2 and notes 3.4 to 3.3 to reflect sequence

  • changed attribute nCubeRef from CDATA to IDRef (3.2.1)

  • removed attributes col, row, colCnv, rowCnv, query from physLoc as they refer to unincorporated elements of a broader proposal

  • inserted explanations of concept in 4.1 and renumbered 4.1.3 through 4.1.6 to reflect insertion

  • added %a.global; to nCube attribute list (4.3)

  • changed attributes other and total to (Y|N) "N" to reflect original design (4.3.18)


MODIFICATIONS by Sanda Ionescu, ICPSR (University of Michigan), 7/15/2002, following the DDI Committee meeting in Washington, D.C., 6/15/2002

  • changed var (4.3) attribute "wgt-var" from IDREF to IDREFS

  • added var attribute "weight"

  • added sumStat (4.3.14) attribute "wgt-var"

  • changed sumStat attribute "weight" from IDREF to IDREFS

  • changed catStat ( and attribute "weight" from IDREF to IDREFS

  • added option "nested" to attribute "type" in fileStrc (3.1.3)

  • added attributes "rtypeloc", "rtypewidth", and "rtypevtype" to recGrp (

  • made elements timeDmns (4.3.12), dmns (4.3.13) and cohort ( and optional and repeatable

  • made element measure (4.3.14) optional and non-repeatable

  • changed contents of elements CubeCoord ( and physLoc ( from PCDATA to EMPTY

  • changed contents of element measure (4.3.14) from (#PCDATA|%a.phrase) to EMPTY

  • changed contents of element p from (#PCDATA|%a.phrase) to (#PCDATA|emph|hi|list)

  • declared formatting elements div, emph, head, hi, itm, list, label according to TEI guidelines

  • changed contents of element othId to (#PCDATA|%a.phrase;|%e.form;)*


MODIFICATIONS made by Sanda Ionescu, ICPSR (Univ. of Michigan), 3/7/2003, following the DDI Committee meeting in Washington, DC, 2/7/2003

  • added element geoBndBox ( with its child elements westBL (, eastBL (, southBL (, and northBL (

  • added element boundPoly ( with its child element polygon (, child element point (, and child elements gringLat ( and gringLon (

  • renumbered elements anlyUnit, universe, dataKind to fit new configuration

  • added attributes country and sdatrefs to generic description of element labl (A.2)

  • added element nCubeGrp (4.2) with subelements labl (4.2.1), txt (4.2.2), concept (4.2.3), defntn (4.2.4), universe (4.2.5), and notes (4.2.6)

  • renumbered var and all its subelements to 4.3 to fit in new configuration

  • added attributes temporal, geog, geoVocab, and catQnty to element var (4.3)

  • added attributes levelno, levelnm, compl, and excls to element catgyGrp (4.3.17)

  • added attribute excls to element catgry (4.3.18)

  • deleted attributes other and total from element catgry (4.3.18)

  • removed recursiveness of element catgry (

  • added element mrow ( with its subelement mi ( to parent element catgry (4.3.18)

  • added element geoMap (4.3.24)

  • renumbered nCube and all its subelements to 4.4 to match new configuration

  • deleted element timeDmns (4.4.12)

  • renumbered nCube subelements dmns, cohort, range, measure, and notes to match new sequence. Also renumbered section 4 notes to 4.5

  • made element measure (4.4.13) optional and repeatable (had previously been non-repeatable)

  • changed declaration of attribute aggrMeth (in var 4.3 and nCube 4.4) from CDATA to (sum|average|count|mode|median|maximum|minimum)

  • changed declaration of attribute nature (in var 4.3) from CDATA to (nominal|ordinal|interval|ratio)

  • changed declaration of attribute additivity (in var 4.3 and nCube 4.4) from CDATA to (stock|flow| non-additive)

  • deleted attribute "nature" from element measure (4.4.13)

  • Bug Fix: Added xml:lang NMTOKEN #IMPLIED (2005-01-25)


MODIFICATIONS made by Sanda Ionescu, ICPSR (Univ. of Michigan) and Mark Diggory (Harvard University) 6/16/2005, to implement Nested Categories proposal.

  • added 4.3.25 Category Level (catLevel)

  • attributes catgry and level added to 4.3.18 Category (catgry) element

  • moved Variable notes to 4.3.26 (notes)