10 Predefined Groups

10.1 Introduction

A Predefined Group Comparison presents your library's or Subscription Group's holdings compared to an OCLC-defined group, that is, to a set of libraries selected by OCLC for the significance and/or specialization of their collections. Libraries may be grouped by type (ARL Libraries), size (Public Libraries by Population Served), specialization (Education, Business & Economics), country (Canada, Ireland) and so on. Groupings are based on sources such as U.S. News & World Report's College and University ratings, Association for Research Libraries statistics, Hennen's American Public Library Ratings (HAPLR) and additional authoritative web sites.

Your library or Subscription Group can also create a Predefined Group Comparison with OCLC's Electronic Books or NetLibrary databases.

The comparison is presented in a spreadsheet-style table called the Analysis Results screen. For a description of screen functions see: section 11.1, "Analysis Results Screen".

Example:

For the 1990-1994 timeframe, the libraries comprising the Real Estate—Undergraduate group hold a collective total of 85, 235 titles. For the same period, the Western Group Subscription Group holds 392 titles.

The complete list of OCLC-defined groups is available at: http://www.oclc.org/support/documentation/collectionanalysis/authlists.html.

Comparisons that you create are identified as Predefined Groups on the Data to Analyze screen.

You must create an Predefined Group Comparison using the WorldCat Services Administrative Module (see chapter 2, Administrative Functions).

Analysis type

Individual institutions.  For libraries subscribing as individual institutions, a Predefined Group Comparison is created between your library's holdings My Library—the Individual Library Analysis) and the selected group.

Subscription Groups.  For libraries subscribing as part of a Subscription Group, the comparison is created between the group's Aggregated Group Analysis and the selected group

See section 1.3, "Types of Analysis" for more information about these analysis types.

Application

For an example of the use of a predefined group by an individual institution, see the OCLC Best Practices presentation Analyze Collection Gaps at: http://www5.oclc.org/downloads/tutorials/wca/acg/analyze_gaps.htm.

10.2 Comparison

Defaults

The default Analysis Results screen presents total titles ( Totals), unique titles ( Unique), and shared titles ( Overlap) as the table columns, and your library/group and the selected authoritative list as rows.

The default row expansion order is:

View graph display

You can view a graph of the data from a single row of the analysis table by selecting the Display Graph  icon. See section 11.2, "Graph Display Screen" for more information.

Changing the analysis

You can vary the order in which dimensions are applied to this analysis by using the Change Analysis screen.

Column values.  For an Predefined Group Comparison the available column values are:

Row expansion.  For row expansion, you may re-order the following dimensions except the one you have selected for the column value:

Limiting the analysis

You can reduce the overall results of an analysis by reducing the breadth of one or more of the dimensions. You reduce the breadth by creating subsets of an analysis dimension on the Limit Analysis Screen screen.

For an Authoritative List Comparison you can select subsets of the following dimensions:

• Library vs Group
• Holding Count
• Division
• Publication Date
• Language
• Format
• Audience

View records

To view actual holdings for a given row/column, select the number shown in the corresponding table cell.

Summary bibliographic information is provided as a List of Records screen. Records are ranked by the number of libraries holding the item in WorldCat, in descending order, that is, items held by the most libraries display first on the list.

To...	Do this...
View additional information about the List of Records screen	Select the Help   icon.
View a full record	Select the record title.
Return to the Analysis Results screen	Select the Collection Analysis tab.

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10.3 Overlap

A Predefined Group Comparison provides an Overlap view which shows the number of titles that your library or your Subscription Group owns jointly with the collective titles (duplicates removed) of the selected OCLC-defined group or database.

For these comparisons Overlap is shown in the Uniqueness tab.

Example: Individual institutions

For this comparison:

• Your library owns a total of 586,101 holdings.
• The Electronic Books database includes 80,225 titles.
• Your library and the Electronic Books database have 32,485 titles in common.

Example: Subscription group

For this comparison:

• The Western Group owns a total of 37,226 titles.
• The Top 10 Law Schools group contains 137,160 titles.
• The Western Group and the Top 10 Law Schools own 26,008 titles in common.

See section 1.7, "Overlap/Uniqueness Implementation" for information on how Overlap totals are counted.

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10.4 Uniqueness

A Predefined Group Comparison provides a Uniqueness view which shows the number of titles that your library or Subscription Group owns that are not also owned by the selected OCLC-defined group or database.

Example: Individual institution

For this comparison:

• Of the 586,101 titles your library owns, 553,616 are not contained in the Electronic Books database.
• Of the 80,225 titles in the Electronic Books database, 47,740 are not owned by your library.

Example: Subscription group

For this comparison:

• Of the 137,160 titles in the Top 10 Law Schools group, 111,152 are not owned by the Western Group.
• Of the 37,226 titles owned by the Western Group, 11,218 are owned by the Top 10 Law Schools group.

See section 1.7, "Overlap/Uniqueness Implementation" for information on how Uniqueness totals are counted.

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