9 Secondary Groups
9.1 Introduction
Libraries who subscribe to WorldCat Collection Analysis as part of a group can create analyses for one or more subsets of their Subscription Group; these smaller groups are called Secondary Groups.
Comparisons that you create are identified as Secondary Groups on the Data to Analyze screen.
You must create a Secondary Group using the WorldCat Services Administrative Module (see chapter 2, Administrative Functions).
Analysis type
Creating a Secondary Group automatically results in both a Group Analysis and an Aggregated Group Analysis for the Secondary Group. See section 1.3, "Types of Analysis" for more information.
back to topDefaults
Information for the Secondary Group is presented in a spreadsheet-style table called the Analysis Results screen. The default Analysis Results screen presents Publication Date ranges as the table columns and the Subscription Group and the Secondary Group as rows. For a description of screen functions see: section 11.1, "Analysis Results Screen".
Example:
This Pacific Coast Secondary Group consists of four members of the Western Group.
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 a Secondary Group analysis you may select one of these dimensions as the column value for the Analysis Results screen:
| Format Language Library | Publication Date Overlap Uniqueness |
Row expansion. For row expansion, you may re-order the following dimensions except the one you have selected for the column value:
| Audience Division Format | Language Library |
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.
For an Secondary Group comparison you can select subsets of the following dimensions:
- Secondary Group Library
- 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. |
9.3 Aggregated Secondary Group
An Aggregated Group Analysis for a Secondary Group combines the titles of all members of the group and then removes duplicates so that the group appears as a single institution. The default Analysis Results screen presents Publication Date ranges as the table columns and the Subscription Group and the OCLC Conspectus divisions.
Example:
Within the Pacific Coast Secondary Group, libraries collectively own 164 Higher Education titles published the 1850-1899 date range.
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 aggregated Secondary Group you may select one of these dimensions as the column value for the Analysis Results screen:
- Format
- Language
- Publication Date
Row expansion. For row expansion, you may re-order the following dimensions except the one you have selected for the column value:
| Audience Division Format | Language Library |
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 aggregated Secondary Group you can select subsets of the following dimensions:
- 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. |
9.4 Overlap
A Secondary Group Analysis provides an Overlap view which shows the number of titles each library in the group holds jointly with every other library in the group.
Example:
Among the members of the Pacific Coast Secondary Group, Simon Fraser University holds:
- 153,456 titles in common with California State University at Long Beach (ORZ)
- 130,153 titles in common with Western Washington University (XFF)
Names vs symbols. The initial display shows library names as the column headings. To change the headings to OCLC symbols select the View Library Symbols link at the top of the Overlap tab.
The table is redrawn with the libraries' OCLC symbols and the link changes to View Library Names.
See section 1.7, "Overlap/Uniqueness Implementation" for details.
Two-member group
A special case occurs when a secondary group has only two members. In this case, the equivalent of Overlap appears in the Shared by 2 column of the Uniqueness tab.
Portland State University and Simon Fraser University hold 218, 427 titles in common.
9.5 Uniqueness
A Secondary Group Analysis provides a Uniqueness view which shows how broadly a given title is shared among the members of the secondary group, that is, how many of a library's titles are held by it alone, and how many are held by one other member ( Shared by two), held by two other members ( Shared by three), by three other members ( Shared by four), and so on.
Example:
Among the members of the Pacific Coast Group, Simon Fraser University has:
- 194,287 titles that no one else in the group owns
- 100,695 titles that are shared with one other member of the group
- 80,670 titles that are shared with two other members of the group
- 54,991 titles that are shared with three other members of the group
See section 1.7, "Overlap/Uniqueness Implementation" for details.