Tuesday, November 30, 2010

Dates in MADS

The MODS Editorial Committee is considering changes to the Metadata Authority Description Schema (MADS).Comments are welcomed.
The MODS Editorial Committee is considering changes to MADS. Some of these will be changes to bring it up to date with changes in MODS 3.4 (and a few things in earlier 3.X versions). Other changes involve accommodating RDA elements, many of which have been added to MARC. We are currently discussing how to express dates in MADS and would like some feedback from the MODS community.

It is desirable to have dates associated with the entity being described in MADS, e.g.. a person or organization. There are several dates in RDA data elements: Date associated with the person (date of birth, date of death,period of activity), Date associated with a family, Date associated with a corporate body (date of conference, establishment, and termination), Date associated with an event. In adding dates associated with the entity to MADS we need to consider how dates are handled in MODS as well as how they would be mapped from MARC.

In MARC authorities we added a field 046 for dates associated with the entity described in the authority record; this field was previously in the bibliographic format. We added separate data elements for:
  • birth date
  • death date
  • date created (start and end)
  • start period
  • end period
The latter could be used for period of activity for a person or date of establishment/termination of an organization. The dates are in a structured form with the encoding scheme identified in a separate data element. This field is considered part of the "general information" about the heading.

In MODS, most of the dates are in originInfo (other than subject dates, which are in subject/temporal) and would not apply to authorities. In MODS and MADS birth and death dates may be included as part of the name heading (to be consistent with headings in MARC) in name/namePart type=”date”. There are some specific types of dates that give additional information about the entity described in the record, and it is desirable to include them in a separate element whether or not they are given as part of the name.

However, dates in MODS do follow a common structure that may be useful to adopt in MADS. MODS date elements use an “encoding” attribute to specify the scheme used to form the date and a “point” attribute with values start and end to indicate date ranges. An element “dateOther” is used for dates not accommodated otherwise with a type attribute to allow the kind of date to be specified, since we could never predict all the possibilities for all applications.

Proposal: For MADS we suggest adding container element . This would be more or less equivalent to what was added to MARC. The proposed list of date subelements for MADS is as follows:

<activePeriod> (with point=start,end)
<dateCreated> (with point=start,end)
<dateOther> (with type and point=start,end)

All dates would have an encoding attribute.

There are many other ways to do this of course (e.g. separate data elements for start and end rather than point attribute).

Comments are welcome.