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SIGNIFICANT PROPERTIES
A. INTRODUCTION
Transformations
NARA’s mission is to preserve and make available the permanently valuable records of
the Federal Government. In determining the best strategies for providing electronic
records for researchers, NARA will employ several different strategies, including
providing access to records in their original formats, emulating the original environment,
and transforming records to different digital file formats. Because we expect there to be
costs associated with transformations, NARA will probably not perform transformations
on a routine basis. For this reason, then, NARA will need to decide when electronic
records need to be transformed. In any case NARA will always retain the version of the
electronic record that it received from the creating entity. In creating transformations,
NARA can use either the original record or a later transformation, depending on which
will provide its users with the most desirable results. The decision to transform records is
driven by either one of two events, or the combination of both:
That the digital file format is at risk of obsolescence, or
That NARA’s research community requires an enhanced level of access.
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Authenticity
When transforming electronic records, the goal is to produce an “authentic version” that
is usable to NARA’s research community. The ERA Requirements Document defines
“authentically preserved” thusly: “To maintain a record over time in such a manner that
its identity is unquestionable and it is not corrupted.”
In order for versions that NARA creates for whatever purpose to be considered
“authentic,” they must:
1. Be free of corruption,
2. Effectively reproduce the significant properties of all records that were
transformed,
3. Capture the attributes and relationships detailed in the Archival Information
Package (AIP) of each record for the new version, and
4. Have documentation of the processes and decisions by which transformations
took place to satisfy the needs of official bodies that may need NARA to
authenticate records.
This conforms to NARA electronic records Preservation Principle 1: “The goal of
NARA’s electronic records preservation program is to be able to produce authentic
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For a fuller development of these themes, see the Transformations White Paper on.
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versions of electronic records that meet the needs of its research communities, including
official bodies that require authentic versions.”
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B. ARCHIVAL INFORMATION PACKAGE (AIP)
As noted above one of the features of an authentic transformation is that it captures the
elements of an Archival Information Package (AIP), a concept that NARA has borrowed
from the Open Archival Information System (OAIS) Reference Model. To the greatest
extent possible, the ERA preservation framework adheres to the OAIS Reference Model.
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The OAIS developed several useful concepts, such as “information packages,” that define
the relationships between a digital object and the contextual metadata that allow it to be
understandable to users. The AIP, for example, is a logical concept that identifies the
relationships between the digital object itself, the software that interprets the object and
the contextual and provenance information that enables users to fully understand the
record. The AIP is the lowest level unit that ERA must manage; in effect these are the
“records” or “aggregates of records.”
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Authenticity then can only be maintained in
transformed versions of a record when all of the relationships and attributes identified in
the AIP of the original record are captured in the new transformed version.
So in practice this means that each of the elements of the AIP must be captured in the
AIP for the transformed version of the record as indicated in Figures 1 and 2 below. All
of this AIP metadata is mandatory for all transformations. This differs from the
discussion of Significant Properties, which follows this section, in that the Significant
Properties relate to those properties that may or may not be persisted over time. The
significant properties that are selected for persistence, however, are also captured in the
AIP of the transformed version.
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Figures 1 and 2 indicate the relationship between the
AIP information in the original digital file relate to the AIP information that must be
captured in the transformed digital file.
For Content Information the following must be captured.
Type of Information
Information Required in the
Transformed Record
Digital Object
Technical information about the
transformed object(s).
Representation Information
Information about the internal relationships
within the object, such as compound
documents or attachments and the software
needed to render the object.
2
See NARA Preservation Conceptual Framework, v 1.0 for a fuller discussion of the Preservation
Principles.
3
See http://public.ccsds.org/publications/archive/650x0b1.pdf.
4
See Appendix A for a full description of the AIP.
5
Refer to the work of the Asset Catalogue Entry (ACE) re-design team for details on where and how the
metadata will be stored.
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Figure 1. Content Information Required in Transformed Objects.
For Preservation Description Information the following types of information must be
captured.
Type of Information
Information Required in the
Transformed Record
Reference Information
Capture the unique identifiers of the new
version, as well as cross references to the
original object.
Provenance Information
Capture the provenance information related
to the original record.
Fixity Information
Capture the authentication mechanisms that
were used to create the transformed copy,
such as the integrity seal.
Context Information
Capture the context information related to
the original record.
Figure 2. Preservation Description Information Required in Transformed Objects.
C. LITERATURE REVIEW
Essential Characteristics
As noted above in the section on authenticity, NARA must be able to reproduce the
significant properties (or essential characteristics) of transformations of electronic records
in order for them to be considered “authentic” so that the research community can use
them effectively. The discussion of “essential characteristics” then begins with an
acknowledgment that in any transformation something is always changed. In some cases
things are added to the transformed version and in other cases things are subtracted. The
question that the essential characteristics discussion focuses on then is whether we care
about what was added or subtracted from the original. Some things are inconsequential
(“non-essential”), while others are critical (“essential”) for a researcher to fully
understand the record. The ERA Requirements Document defines “essential
characteristics” as: “Those properties/characteristics of electronic records that must
remain unchanged through transfer, ingest, storage, and presentation or output of
records.” The issue becomes how best to apply this concept to NARA’s electronic
records program in a way that is scalable and extensible.
Several years ago, NARA appointed an Essential Characteristics (EC) Team to explore
this issue. The EC Team concluded that the essential characteristics of a series of records
“are found at the intersection of the record type, data type, and the series context in which
they are created.”
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EC Team, “Essential Characteristics (And Attributes) of Electronic Records,” p. 1.
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The EC Team defined the “record type” as: “The intellectual form of the documentary
material, such as a textual record (letter, memo, greeting card), digital photograph, and
web record.” The EC Team used the following list of “record types” on which to develop
their analysis of characteristics that they deemed essential for electronic records. They
began their analysis with the formats for which NARA had developed transfer guidance.
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Digital Record Types
Email
Databases
Digital Photography
Geographical Information Systems (GIS)
Textual (products of office automation software)
Web Records
Figure 3. EC Team’s List of Digital Record Types.
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More recently the Technical Analysis Team (TAT) team developed draft essential
characteristics analyses for the following additional records types:
Digital Record Types
Sound Recordings
Moving Images
Figure 4. TAT Team’s additions to Digital Records Types List.
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The EC Team then developed an Essential Characteristics framework in which they
defined general characteristics about any electronic record. These characteristics are
listed below. The full set of sub-characteristics under each of these four headings can be
found in Appendix C.
Definition
Characteristics related to the visual presentation of
records.
Characteristics that allow interaction with the
records.
7
For the full text of the transfer guidance, see http://www.archives.gov/records-mgmt/initiatives/erm-
guidance.html.
8
See Appendix B for the full definitions for each Record Type.
9
See Appendix B for the full definitions for each Record Type.
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Definition
The organizational, functional, and operational
circumstances surrounding materials’ creation,
receipt, storage, or use, and its relationship to other
materials. Most of these characteristics are not
intrinsic to the records themselves but include a
collection of information that is both internal and
external to the records.
The characteristics that define how record elements
are organized and interrelated. Note: While
embedded or hyperlinked content may be found
across record types, we may not know much about its
structure, data type, or record type. We cannot
capture every possible structural nuance of the
records.
Figure 5. EC Team’s Definitions of Each Essential Characteristic.
For each Digital Record Type, the EC Team developed an analysis and a template in
which they identified the core (i.e., mandatory) and conditional (i.e., optional) sub-
characteristics for that Digital Record Type. So, for example, appearance characteristics
are far more important (core) for digital photography than for textual materials, where
they are listed as optional (conditional). A full list of characteristics and sub-
characteristics is provided in Appendix D.
Significant Properties
While NARA’s EC Team was developing its framework, The National Archives (UK),
assigned a team to explore a similar concept they called “significant properties.” In a
report sponsored by the Arts and Humanities Data Service (AHDS), project director
Gareth Knight defined “significant properties” as “the characteristics of digital objects
that must be preserved over time in order to ensure their continued accessibility,
usability, and meaning of the records.”
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The UK Team grounded their work in the
PREMIS Data Dictionary Model, which is the model that NARA will be using in
Increment 3 for managing metadata in its Asset Catalogue Entry (ACE). PREMIS
defines significant properties as: “Characteristics of a particular object subjectively
determined to be important to maintain through preservation actions.”
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The UK Team
identified five categories of significant properties, as shown in Figure 6 below.
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Gareth Knight, Framework for Definition of Significant Properties, 3/12/2009, InSPECT Project
document, AHDS.
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Property
Characteristic
Content
Content is the abstract term to describe the expression of intellectual
work. In a digital environment, Content may describe text, still and
moving images, audio, and other intellectual products. EX: logical
properties, duration, character count.
Context
Context may be applied to any information contained in the digital
record that describes the environment in which the Context was created
or that affects its intended meaning. Ex: Creator name, date of
creation, description of the intellectual work, computer environment in
which the Source was created (possibly).
Structure
Structure refers to any information that describes the relationship
between two or more types of content, as required to reconstruct its
performance. It may be applied to the intrinsic or extrinsic
relationships contained in the performance. Ex: E-mail with
attachments.
Rendering
The rendering category refers to any information that contributes to the
re-creation of the performance. For example, it may be applied to the
visual or audible Component. Ex: font type, color and size, and bit
depth.
Behavior
Behavior is applicable to any information that describes the method in
which the Content interacts with other stimuli. Stimuli may include the
interaction of the user with the software, or interaction with other
sources of information, such as an external resource that affects the
content, context, structure, or appearance of the resources. Behavior is
considered to be the most difficult characteristic to preserve - it is often
tied to the capabilities of a particular software applications and may be
difficult to translate. It is also difficult to define all behavioral
characteristics in a quantitative manner. Ex: hyperlinks.
Figure 6. TNA’s Definitions of Significant Properties.
In their initial report, the UK Team went on to apply their methodology to the following
Digital Record Types: structured text, raster images, digital audio, and email.
D. UTILIZING THESE CONCEPTS IN ERA
As can be seen from the brief analysis presented above, there is a high degree of overlap
between these two groups in terms of what properties must be persisted over time and in
how to apply the concepts to archival electronic records. How can these concepts be
employed effectively by NARA?
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Terminology
We propose to use the phrase “significant properties,” instead of “essential
characteristics,” because it seems to have wider usage in the digital preservation
community and because it is what is used in PREMIS, the metadata model that NARA
has adopted to manage metadata about its ERA’s assets.
Definition
We propose to use the definition that the UK Team developed for significant properties:
“The characteristics of digital objects that must be preserved over time in order to ensure
their continued accessibility, usability, and meaning of the records.” This definition’s
stress on the usability of digital records to the research community seems more in line
with ERA’s goal in determining when to transform records: “Are members of the
research community who are likely to want to use a record, reasonably able to render and
use it to meet their research needs?”
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Specific Significant Properties
The EC and UK Teams independently produced almost identical lists of significant
properties/essential characteristics, as can be seen in the matrix presented in Figure 7
below. We propose that NARA use the list of characteristics and definitions developed
by the EC Team.
EC Team Characteristics
UK Team Properties
Comparison
Appearance
Rendering
Virtually identical
Behavior
Behavior
Virtually identical
Context
Context
Virtually identical
Structure
Structure
Virtually identical
Content
Not included in the EC
Team list.
Figure 7: Comparison of Specific Significant Properties/Essential
Characteristics.
When are Properties Significant?
12
See Transformations White Paper.
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The EC Team noted that what made a characteristic “essential” depended on elements
such as the “record type, data type, and the series context in which they are created.”
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The UK Team came to similar conclusions. To ignore the Digital Record Type, series,
and digital type in employing the concept would be to adopt a one size fits all approach
where appearance or behavior, for example, is always significant regardless of the Digital
Record Type or intellectual content of the material. We believe that this position is
untenable.
The two teams agreed that some properties of digital files were significant in some cases
and not significant or inconsequential in others. They also agreed that the Digital Record
Type was a useful discriminator in deciding when a property was significant or not.
Finally, they both came to the conclusion that appearance, behavior, and structure could
be significant in some cases and not significant in others, but that context and content
were always significant. so there is no need for archivists to make any further judgments
about these properties. So we propose that NARA implement a significant properties
approach in preserving electronic records. But is the concept scalable and extensible in
the real world?
Scalable and Extensible?
Scalable. How can a concept that is sensitive to individual variation be applied to the
holdings of an institution that has so much diversity in its holdings such as NARA?
Applying the concept of trying to decide which properties must be persisted at the digital
file level is clearly not scalable. NARA expects to receive millions of digital files in the
coming years, so this option, even if it were desirable, is simply not practical. NARA can
clearly use its staff resources to better advantage. But if NARA developed default
significant properties templates for each Digital Record Type and applied the concept at
the record type and transfer group/series level, the amount of human involvement in the
process could be doable with existing staff resources. This may be more difficult in
aggregates that are not homogenous with respect to Digital Record Type. NARA will
need to run some paper tests on the concept to assure itself that the concept will work in
this area.
We propose that NARA ask the significant properties question about the series or transfer
group at the point at which NARA is considering transforming a record. Archivists
would review information about the transfer group or series, confirm the Digital Record
Type, and decide if the default significant properties for that Digital Record Type will
apply to the body of records in question. If not, then they would change a property from
being optional to being mandatory or vice versa. This would help inform the
transformation plan that would be worked out between Records Preservers and Reference
Archivists.
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If not, the archivist could revise the template for that particular transfer
group/series.
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EC Team, “Essential Characteristics (And Attributes) of Electronic Records,” p. 1.
14
See the Transformation white paper for a full discussion of the development of transformation plans.
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Extensible. How can NARA apply this concept to the wide variety of digital file formats
and Digital Record Types that NARA currently has among its holdings and expects to
accession in the near future?
The EC Team has already developed templates for six Digital Record Types and the
Technical Analysis Team (TAT) has developed draft significant property templates for
two additional ones (sound recordings and moving images). Based on the General
Record Type list from NARA 1301 of the Record Types that might be electronic,
excluding things like bound volumes and artifacts, the only Digital Record Type for
which NARA has not developed a Digital Record Type template is architectural and
engineering drawings. In reviewing the list of electronic records that the Accessioning
and Ingest Team found that NARA has currently among its holdings, the existing Digital
Record Type templates will cover all of them, except for architectural and engineering
drawings. Aside from developing a template for architectural and engineering drawings,
the only Digital Record Type that NARA will need to develop is Office Automation files,
where a creator transferred to NARA digital files from typical office automation
products, such as Word, Excel, and PowerPoint. The list of Digital Record Types and the
status of templates is presented in Figure 8 below.
Digital Record Types
Status
Email
Completed
Databases
Completed
Digital Photographs
Completed
GIS Records
Completed
Textual Records
Completed
Web Pages
Completed
Sound Recordings
TAT draft
completed
Moving Images
TAT draft
completed
Architectural and Engineering Drawings
Not done
Office Automation Files
Not done
Figure 8: List of Digital Record Type Templates and Status
Conclusions
We propose the following:
NARA archivists make significant properties determinations about aggregates of
electronic records (series and transfer groups) and only rarely about individual
files.
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In making significant properties determinations, NARA archivists take into
account the intellectual content and Digital Record Type of the records that are to
be transformed.
NARA will use the templates developed by the EC Team as default templates for
the Digital Record Types that have been defined by the EC Team. NARA will
refine those templates as they gain experience using the tools.
If NARA archivists encounter new Digital Record Types, they will develop new
Significant Properties Templates.
Archivists make significant properties determinations at the point at which for
whatever reason, NARA determines that a transformations is necessary.
Archivists make significant properties decisions about appearance, behavior, and
structure properties, based on the definitions and methodology that the EC Team
developed.
NARA always considers context and content properties, as defined by the EC and
UK Teams to be significant and therefore the metadata related to content and
context are always incorporated into the AIP of the transformed version, based on
the guidance provided in Figures 1 and 2 above.
Once archivists make significant properties determinations, they are recorded in
the Transformation Plan for the aggregate. If determinations are made at the
digital file level, then that is where they are recorded.
Once archivists make significant properties determinations about a series of
records, records preservers work with archivists to determine how the properties
can be implemented in a transformation. So for example, if an archivist
determines that color is important to a faithful rendering of a color photograph,
records preservers will work with archivists on the correct the color palette for
that series of digital photographs.
Records preservers, as part of their research, explore the characteristics of
transformation tools to learn what elements are added or subtracted from digital
files during transformations. This is stored in a knowledge management system
for use by other records preservers and eventually for the international community
of records preservers. In instances when Records Preservers determine that a
format that is obsolete or highly obsolescent, and in need of transformation and no
transformation path is yet available that meets the significant properties
requirements of NARA, they will work with the Records Processors to determine
appropriate fallback strategies, while NARA awaits a solution that will meet all of
its needs.
Regardless of what is decided concerning transformations, the metadata about the
transformed version is captured in the AIP for each transformed record. See the
AIP discussion above.
E. TRANSFORMATION SCENARIOS
The following examples are meant to give practical illustrations of how the concept
might be applied to NARA’s records. NARA transforms records as part of a broad
strategy that addresses issues of digital file format obsolescence and meeting the needs of
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user communities.
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Regardless of whether the proposed transformation is done for
preservation or reference purposes, Records Preservers and Reference Archivists
collaborate in developing a Transformation Plan.
At the time of a proposed transformation, Reference Archivists review the records and
the documentation NARA received about the records being considered for transformation
to gain insights into how the records are structured and how they are and might be used
by the research community. They also consult with members of the research community
as appropriate. Based on their review, Archivists confirm the Digital Record Type(s) and
digital file formats of the target series. If the Digital Record Type(s) are in error, the
Archivists make the necessary corrections. Archivists then refer to the Significant
Properties Digital Record Type Templates that correspond to the Digital Record Type(s)
in the target series. Archivists review the questions in the template for appearance,
behavior, and structure and determine whether the default properties in the template
should be accepted or changed. The following examples are meant to be illustrative of
how the process might work.
1. One Series with one Digital Record Type on one format. NARA
determines that a series of 50,000 digital photographs that are all JPEGs
need to be transformed. An archivist reviews the digital files and confirms
that the Digital Record Type for the series is in fact Digital Photography
and that the digital file format is JPEG. The default significant properties
for photographs are as follows:
Digital Photography
Significant Properties
Core
Conditional
Appearance
Layout/Size
Appearance
Layout/Orientation
Appearance
Color
Behavior
Display
Structure
Compression
Structure
Bit Depth
Structure
Resolution
Figure 9. Significant properties for Digital Photographs
The archivist examines the photographs, as well as the documentation related to the
accession and determines that the default settings for the Appearance, Behavior, and
Structure properties are appropriate. In other words it is critical that the size, orientation
of the photograph, and its colors must be faithfully rendered in the transformation in
order to ensure that researchers can make sense of the records. Likewise for Behavior,
the user must be able to have the photograph displayed. Finally the Structure properties,
15
See the Transformations white paper for a fuller discussion of the transformation process.
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such as bit depth, compression, and resolution are critical to making sense of the
photography. This decision is recorded in the Transformation Plan and the AIP for each
transformed record in the series.
2. One series with one Digital Record Type and more than one format.
NARA determines that a series of web pages needs to be transformed.
The web series of 100 files, which are in the following digital file formats:
html, GIF, and PDF. An archivist reviews the files and the accessioning
documentation and confirms that the Digital Record Type for this series is
web pages and that the digital file format types are correct. The default
significant properties for web pages are as follows:
Web Pages
Significant Properties
Core
Conditional
Appearance
Layout
Appearance
Text
Structure
Schema - Is the website
dynamic and database
driven? Then refer to EC for
database Digital Record Type
Structure
Schema/Linkage If there is
linked content from different
domain it should be
redirected and considered an
EC if associated with a
formal agreement (see
NARA Web Record
Guidance)
Structure
Sequence
Figure 10. Significant Properties for Web Pages
The accessioning archivist examines the web pages. In the case of the conditional
property “structure/schema/linkages,” the documentation from the transferring entity
indicates that there was no formal agreement between NARA and the transferring entity
to maintain these links. The archivist determines that it is not worth the effort to maintain
these external links. The external links in this case are, therefore, deemed not significant.
The archivist determines, however, that the research community would benefit from
maintaining links internal to the web pages that were transferred and that the
documentation of the links and the manner in which they were executed would make the
task of preserving the links feasible. So the archivist recommends that the links internal
to the web site become significant for this accession. This decision is recorded in the
Transformation Plan and it the AIP for each transformed record in the series.
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Next Steps/Follow Up
1. Where would the information about significant properties be recorded? We have
talked about using the LMP in the past, but the LMP concept cannot be used for
presidential, congressional, Supreme Court, donated, or surrogates, and we clearly
want to use these concepts for all of NARA electronic records holdings.
2. NARA needs to review the EC Team’s Significant Properties Templates and
decide if they are correct.
3. Review the UK Team’s work and see if we can use any of their findings to
enhance our analyses of Digital Record Type templates.
4. Review the list of digital format types and Digital Record Types from the ERA
Accessioning & Ingest IPT. Can the current Digital Record Type Templates
cover them all?
5. We need to define the Digital Record Types.
6. We should run some paper experiments on this against know series to be sure we
are right. How well will our model work on heterogeneous aggregates? Need to
run some paper tests on this.
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Appendix A. The OAIS Definition of the Archival
Information Package (AIP)
According to OAIS each AIP is composed of Content Information and Preservation
Descriptive Information. A graphical depiction is also provided.
Content information - The set of information that is the original target of preservation.
It is an Information Object comprised of its Content Data Object and its
Representation Information. An example of Content Information could be a single
table of numbers representing, and understandable as, temperatures, but excluding the
documentation that would explain its history and origin, how it relates to other
observations, etc.
Content Data Object: The Data Object that together with associated
Representation Information is the original target of preservation.
Representation information - The information that maps a Data Object into
more meaningful concepts.
Preservation Description Information (PDI): The information which is necessary for
adequate preservation of the Content Information and which can be categorized as
Provenance, Reference, Fixity, and Context information.
Provenance information - The information that documents the history of the
Content Information. This information tells the origin or source of the Content
Information, any changes that may have taken place since it was originated,
and who has had custody of it since it was originated.
Reference information - The information that identifies, and if necessary
describes, one or more mechanisms used to provide assigned identifiers for
the Content Information. It also provides identifiers that allow outside systems
to refer, unambiguously, to a particular Content Information.
Fixity information - The information which documents the authentication
mechanisms and provides authentication keys to ensure that the Content
Information object has not been altered in an undocumented manner
Context information - The information .that documents the relationships of the
Content Information to its environment. This includes why the Content
Information was created and how it relates to other Content Information
objects.
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Appendix B. EC Team’s List of Digital Record Types with
Definitions, Plus TAT’s Team’s Additions
EC Team’s List of Record Types
Email. “A document created or received via an electronic mail system,
including brief notes, formal or substantive narrative documents, and any
attachments, such as word processing and other electronic documents,
which may be transmitted with the message.”
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Databases. “Information that is accessed and updated through software (a
database management system) that has been organized, structured, and
stored so that it can be manipulated and extracted for various purposes.
For purposes of identifying characteristics for Increment One and Two, we
will be analyzing databases as a traditional schedule item and not associated
with large institutional data repositories and associated data mining
techniques.”
17
Digital Photography. “Digital photography, as opposed to film
photography, uses electronic devices to record the image as binary data.”
18
GIS. “A geographic information or geographical information system
(GIS) is a system for creating, storing, analyzing and managing spatial
data and associated attributes. In the strictest sense, it is a computer system
capable of integrating, storing, editing, analyzing, sharing, and displaying
geographically-referenced information. In a more generic sense, GIS is a
tool that allows users to perform queries, analyze the spatial information,
and present data in a variety of ways.”
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Textual (products of office automation). “Examples: minutes of
meetings, organizational charts, diaries, calendars, correspondence,
reports, briefing books, legal opinions, directives, and publications.
Textural Records may be in electronic form, as in the case of some email
records or word processing documents.”
20
Web. “Identification of essential characteristics for Web Records
addresses Web content records only. For management and operation web
records see other record types.
Web Content Record. A collection of information, documents, or database
that is sent from a server to a browser via Hypertext Transfer Protocol
(HTTP), when a URL has been activated and meets the definition of Federal
record and is provided via an agency’s web site. Web content can be static or
16
EC Team, “Essential Characteristics – Email,” p. 1
17
EC Team, “Essential Characteristics – Databases,” p. 1
18
EC Team, “Essential Characteristics – Digital Photography,” p. 1
19
EC Team, “Essential Characteristics – GIS,” p. 1
20
EC Team, “Essential Characteristics – Textual (products of Office Automation,” p. 1
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dynamic. (If dynamic, you may encounter another record type, such as a
database).”
21
TAT Team’s additions to the list of Digital Record Types.
Sound recordings. “Like moving images, sound recordings are time-based,
meaning that they are dependant upon technology and have duration as a
dimension. They are basically a moving waveform expressed in binary data.
Digital sound represents the analogue waveforms using sampling methods that
convert the shape of the wave over time into a series of numbers.”
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Moving Images. “Moving images consist of a succession of still images and may
also include a sound component. They are time-based, meaning that they are
dependant upon technology and have duration as a dimension. Moving image and
sound recordings have significantly more complex characteristics than most other
digital resources. Digital moving images use electronic devices to record the
sequence of images and audio waveforms as binary data. Playing back these
images at particular speeds conveys the illusion of movement while bit rate
controls the audio speed.”
23
21
EC Team, “Essential Characteristics – Web,” p. 1
22
TAT, “Essential Characteristics – Sound Recordings,” p. 1
23
TAT, “Essential Characteristics – Moving Images,” p. 1
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Appendix C: EC Team’s Definitions of Characteristics
Appearance
Definition: Characteristics related to the visual presentation of records.
General questions
Is the record’s appearance fixed or mutable?
Would a change in the record’s appearance alter its meaning?
Does changing the record’s appearance diminish its value?
Behavior
Characteristics that allow interaction with the records.
General questions
Are there elements of the user interface or system behaviors that must be
maintained in order to understand how the agency used the records?
Are there elements of the user interface or system behaviors that must be
maintained in order to use the records as the agency did?
Which, if any, of these elements are intrinsic to the record?
Context
The organizational, functional, and operational circumstances surrounding
materials’ creation, receipt, storage, or use, and its relationship to other materials.
Most of these characteristics are not intrinsic to the records themselves but
includes a collection of information that is both internal and external to the
records.
General questions
Will the context characteristic affect other characteristics of the record type?
Do the answers to the context questions affect the preservation of other
appearance or behavior characteristics? For example, if the records have been
appraised as permanent for their informational value, and not evidential, then
appearance characteristics may not need preserved.
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Structure
The characteristics that define how record elements are organized and
interrelated. Note: While embedded or hyperlinked content may be found across
record types, we may not know much about its structure, data type, or record type.
We cannot capture every possible structural nuance of the records.
General questions
Would a change in the record’s technical structure alter its appearance?
Would a change in the record’s technical structure affect its possible
behaviors?”
24
24
EC Team, “Essential Characteristics (And Attributes) of Electronic Records,” pp. 1-4.
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Appendix D: Essential Characteristics (EC) for Digital
Record Types
Summary Document
(For background refer to five EC Definitions Documents)
Record Type
Characteristic
Core
Conditional
Questions
Database
Behavioral
Manipulate
Behavioral
Query
Does the query demonstrate how
the agency used/interpreted the
data for decision-making, legal
use, or general accountability. Is
it a reflection of how an agency
made a decision? If yes, then
determine if the results display
was saved to some other format
for reporting purposes. If no,
then, query is an EC.
Behavioral
Display of report of graph
from query
Is the display in the form of a
report? See other record type
such as textual records (.pdf,
.doc) or web record for EC.
Is the display in a GIS, then
graph and plot are EC. Also see
GIS record type (map) for other
functionalities that are essential.
Context
Series
Context
Descriptive Metadata
If present, then essential.
Structure
Schema
Structure
Character
Encoding
Digital
Photography
Appearance
Layout/Size
Appearance
Layout/Orienta
tion
Appearance
Color
Behavioral
Display
Context
Series
Context
Descriptive Metadata
If present, then essential.
Structure
Compression
Structure
Bit Depth
Structure
Resolution
Email
Appearance
Text/Font
Essential if the text
displayed in message body
bears meaning through
formatting.
Appearance
Text/Orientation
Essential if the text
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displayed in message body
bears meaning through
formatting.
Appearance
Text/Color
Essential if the text
displayed in message body
bears meaning through
formatting.
Appearance
Layout
Are there any overall visual
layout characteristics or structure
of highly recognizable email
“formats” such as State
Department cables, EOP ARMS
email, or Defense Messaging
System? Then this visual
layout/structure is an EC.
Context
Series
Context
Series/Original Order
Is the email transferred in
distinct folders or
directories that reflect a
clear operational structure?
Or segregated and
transferred by blocks of
time, such as by week or
month? Then this structure
is an EC.
Context
Descriptive Metadata
If present, then essential.
Includes transactional
metadata such as read
receipts, rules, message
tracking, threading, etc.
that may be essential if
needed for evidential
value.
Structure
Schema
Structure
Schema/Linkage
If present, does the linkage
provide a complete record;
if a reference to an
attachment is present in
email, both the reference
and the attachment must be
preserved as essential.
Structure
Schema/Lists
If distribution lists are
used, they must be
preserved to provide a
complete record.
GIS
Appearance
Layout
Text Formatting
Is the formatting evidence of
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how the maps were used or
displayed by the creator?
Color
Are there distinctions between
colors that are necessary to
understand the attributes and
overlays?
Behavior
Query
As to which queries or what
querying capabilities are
essential:
Is the GIS used for decision
making in specific cases? If yes,
preserve particular queries and
displays.
Is the GIS used for analytic
purposes? If yes, preserve ad
hoc querying capability.
Manipulate
Is the GIS’s meaning and value
found in how map attributes are
manipulated? If yes, these
behaviors are essential.
Context
Series
Context
Descriptive Metadata
If present, then essential.
Structure
Layers
Linkage
Web
Appearance
Layout
Appearance
Text
Context
Series
Context
Descriptive Metadata
If present, then essential.
Structure
Schema
Is the website dynamic and
database driven? Then refer to
EC for database record type.
Structure
Schema/Linkage
If there is linked content from
different domain it should be
redirected and considered an EC
if associated with a formal
agreement (see NARA Web
Record Guidance)
Structure
Sequence
Essential Characteristics (EC) for Textual Records
Summary Document
Record Type
Characteristic
Core
Conditional
Questions
Text
Appearance
Layout/Size
Is appearance fixed (as in a
publication)?
Appearance
Layout/Sequence
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Appearance
Layout/Pagination
Appearance
Layout/Proportion
Is appearance fixed (as in a
publication)?
Appearance
Layout/Orientation
Appearance
Text/Font
Is appearance fixed (as in a
publication)?
Appearance
Text/Orientation
Appearance
Text/Color
Is appearance fixed (as in a
publication)?
Appearance
Color
Is appearance fixed (as in a
publication)
Context
Series
Context
Descriptive Metadata
If present, then essential.
Structure
Schema/Linkage
If links to other text
records are present, then
essential.
Structure
Schema/Template
If needed to generate record,
then essential
Structure
Character Encoding
Is the encoding scheme the only
one that can manifest the special
characters?
Structure
Compression
If record is a scanned image (e.g.
TIFF), then could be essential
Structure
Bit Depth
If record is a scanned
image (e.g. TIFF), then
could be essential
Structure
Resolution
If record is a scanned
image (e.g. TIFF), then
could be essential