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Module 5a: Authority Control and Encoding Schemes IMT530: Organization of Information Resources Winter 2007 Michael Crandall.

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Presentation on theme: "Module 5a: Authority Control and Encoding Schemes IMT530: Organization of Information Resources Winter 2007 Michael Crandall."— Presentation transcript:

1 Module 5a: Authority Control and Encoding Schemes IMT530: Organization of Information Resources Winter 2007 Michael Crandall

2 IMT530- Organization of Information Resources2 Recap Descriptive metadata elements can be used for access or selection Users don’t know what’s in your information system unless you make it explicit Cutter’s Objects of the Catalog –To enable a person to find a book where the author, title or subject is known –To show what the library has by a given author on a given subject in a given kind of literature –To assist in the choice of a book as to its edition or its character

3 IMT530- Organization of Information Resources3 Module 5a Outline Metadata can be used in many ways Why authority control? Controlled vs. uncontrolled values Principles of authority control Examples of authority control in libraries How does it work? Why do it? Some issues in authority control Alternatives

4 IMT530- Organization of Information Resources4 Metadata can be Used Many Ways It should be obvious by now that metadata may be constructed for a particular purpose, but used in many ways –Descriptive metadata can be used for access –Administrative metadata can be used for description –Structural metadata may be used for administration –All may be used for management or control –Users may need access through unexpected pathways Underscores importance of providing ways to manage creation of metadata for consistency

5 IMT530- Organization of Information Resources5 Why Authority Control? In the library world, authority control is used to ensure that Cutter’s Objects are satisfied- all items can be brought together while enabling known items to be found It solves problems of inconsistency and variation of forms of names, titles, etc. found on physical manifestations of items But it also provides access to variant names through cross-references It establishes a uniform heading to group related items (collocation) It guarantees that bibliographic entities, like authors, will have unique names so that the user can distinguish between those that share a common name

6 IMT530- Organization of Information Resources6 A Broader Definition In non-library settings, Cutter’s Objects can be seen to include many other means of access –May want to group items of a particular file type, in a particular language, from a specific organization So, to generalize, any set of controlled values or rules governing the use of a metadata element could be considered authority control or an encoding scheme Thinking of it this way helps to provide the means to translate the principles into the metadata world, and links back to database modeling –One lack in many database systems is a set of clear rules for determining values in fields –Ends up with the well-known dirty data problem, which eats up lots of admin time in cleanup activities

7 IMT530- Organization of Information Resources7 Controlled vs. Uncontrolled Values Values for uncontrolled metadata elements are either copied from the information object directly or applied without rules –Examples are the title of a web page, or the number of pages in a book Values for controlled metadata elements are defined by rules –We saw some examples of this last week in the Dublin Core encoding schemes used for defining allowed values in some of the elements Control may be simple or complex –Rules defining a specific format (e.g., date) or a pre-defined selection of values (e.g., language codes or format types) for a value can be applied easily –More complex control may be needed where relationships between different values are important (forms of a person’s name, subject hierarchies, etc.)

8 IMT530- Organization of Information Resources8 Process of Name Authority Control Select a single and unique form of a name and enter (use that form as a value in) all records under that uniform name or heading Provide cross-references from the names not selected as preferred headings to the preferred name In library catalogs, authority control provided for names of persons, corporate bodies, etc., but not consistently for works.

9 IMT530- Organization of Information Resources9 Cross-References Equivalence relationships to control for variant names (see references) –Examples : Sears, M.E., search under Sears, Minnie Earl. –United States Library of Congress search under Library of Congress Associative relationships for establishing relationships among different entities (see also references) –Examples : Day Lewis, C. search also under Nicholas Blake Hierarchical relationships are also possible, but we will focus more on these in the subject part of the course

10 IMT530- Organization of Information Resources10 Sample Authority Record

11 IMT530- Organization of Information Resources11 See Reference Example see reference field code in MARC Authorized name field code in MARC

12 IMT530- Organization of Information Resources12 See Also Reference Example

13 IMT530- Organization of Information Resources13 How Does it Work? To manage authority control, a storage mechanism must be created to hold the values and their associations (database, XML schema) –Usually in an authority control file –Holds the records for each authorized entry, its associations and relationships, and change history At time of use, content items are associated with authority records through metadata –Result is a display that satisfies Cutter’s Objects by bringing items with the same heading together and provide direct access to known items

14 IMT530- Organization of Information Resources14 How It Works Vocabulary and Schema Database Site Server indexes Search DLL Modified string Search results Input query XML

15 IMT530- Organization of Information Resources15 Problems with Authority Control Ayres’ article points out some issues with authority control –These are no different than common data maintenance issues in any large system –The difficulty here is that they defeat the purpose of the control in the first place –Again, points out the need to make sure you have good processes and authority rules in place, and make the use of your control as easy as possible at the point of data entry You may decide that authority control is not appropriate if you can’t provide resources

16 IMT530- Organization of Information Resources16 Borbinha and Gorman Does Borbinha’s discussion of authority control map to what we’ve been talking about? What does Gorman think of the Dublin Core and metadata in general in regard to authority control? –Do you agree with him? –Do you see why he might think the way he does after reading Borbinha?

17 IMT530- Organization of Information Resources17 Why Would You Do This? If you’re not in a library, is this kind of control worth your time, or possible? You’ll usually use legacy data for names –HR database is a primary source –Often have an LDAP server as well –Rarely is rigid authority control used in these systems, and downstream users pay for it In intranet applications, integrating user identities can be a huge problem because authority control has not been used

18 IMT530- Organization of Information Resources18 Sweet Spots Corporate names –Essential in managing customer relationship data –Often can be purchased from outside vendors (Dow Jones, Reuters) who maintain for their own purposes Organization names –Often one of the most important access points for users in an intranet –Rarely have access outside your own group –Cross-company exposure can be very valuable People names –But make sure you work with HR and IT organizations to build on their activity

19 IMT530- Organization of Information Resources19 Other Elements Any metadata element you’re using can benefit from authority control or an encoding scheme (in the broad sense we explored earlier in the class) –Even if you don’t need anything more than a rule, make it explicit and if possible build it into your data entry system (e.g., date formats) –If you have choices for term entry, define the values and restrict users to those alone (e.g., language codes, mime types, etc.) –Where possible, use standards for your reference to avoid in-house maintenance

20 IMT530- Organization of Information Resources20 Alternatives to Authority Control Automatic indexing attempts to replicate many of the results of authority control –There are many methods for this, some very time consuming, some processing intensive –Research applications are gradually being incorporated into products Decision on when to use remains the same –What are your requirements for accuracy? –What are your business objectives? –What do your users need? Often a combination is the best solution –Use each where it makes the best business sense

21 IMT530- Organization of Information Resources21 Mid-Term Assignment Part 2: Authority Control for Your Metadata Elements Due at beginning of class Week 6 20% of final grade Spend some time examining the resources you draw your elements from so that you can provide control Think about the people actually describing the content, and how they will know how to populate your elements with consistent values Don’t work on subject elements, those are for your final assignment

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