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Correlation Tool

Video tutorial available.

The Correlation tool facilitates concept tracking by showing you the level of correlation (the ratio of common documents) between groups . For example, you can compare themes by geographical area, sources, languages, or one theme by another.

You can see which documents or groups have been selected elsewhere, and select groups or cells from Correlation itself. See Selecting Documents below.

To see a breakdown of ratings by group and by cell, choose SettingsSettings button on the Correlation Tool> Color by Basic Group Ratings. See Correlation: Group Ratings for details.

Setting Up a Correlation

Using the Row/Column Chooser

  1. Open the Correlation tool by clicking the CorrelationCorrelation Buttonbutton on the IN-SPIRE main toolbar or choosing Tools >Correlation ButtonCorrelation from the menu, and the Correlation tool window displays.

    handy tipOnce the Correlation tool is open, you can specify which rows and columns are used by clicking the Choose Choose button in the Correlation toolbutton to display the Row and Column Chooser window:
    Row Column Chooser window
  2. In the Row and Column Chooser: From the list of Groups on the left, highlight groups you want to use as columns, and click the right-arrow Right arrow button button to add them to the Columns list.
  3. Choose rows in the same way you chose columns. Highlight groups in the list of Groups on the left, and click the right-arrow Right arrow button button to add them to the Rows list.

    Edit the lists if you like by removing groups or reordering them:

  4. Click OK to generate a correlation matrix using the rows and columns you have just chosen.

    Correlation tool window showing by groups

Syncing Rows or Columns with the Groups Tool

Another way of organizing the matrix is to make the groups highlighted in the Groups tool actually drive the rows, the columns, or both rows and columns in Correlation by syncing them with the Groups tool. Which groups are displayed and the order of the groups in Correlation will then depend solely on which groups are highlighted in the Groups tool and their order. To sync rows or columns with the Groups tool:

  1. When Correlation is open, click the Choose Choose button in the Correlation toolbutton to open the Row and Column Chooser.
  2. Select the checkbox for Sync with Groups Tool for columns, rows, or for both.

Dragging and Dropping Groups into Correlation

You can add a group to a row or column in Correlation by dragging it from the Groups tool onto the Correlation window. If you have a Correlation set up already, this is a convenient way to add a group. You can even specify where in the order you want to place it.
If there are no rows or columns in Correlation yet, drag and drop will not be enabled.

  1. In the Groups panel on the right sidebar: highlight one or more groups.
  2. Open Correlation.
  3. Click on one of the highlighted groups in the Groups tool. and drag it to either the row labels area or the column headers area in Correlation. The cursor should look like a rectangle with an attached arrow when it is over an area where groups can be dropped. Notice that if you move the cursor over a matrix cell, it will change to a "forbidden" symbol. and you will not be able to drop the group there.

    The appearance of the cursor before a group can be dropped into Correlation and added as a column

  4. Position the cursor between the two rows or two columns where you would like to add the highlighted group(s). (There will be no visible indication where the groups will be inserted.) Release the mouse button. The groups will become columns in the matrix.

Ordering Rows and Columns

Dragging and Dropping Rows

Column order is set in the Row and Column Chooser. Row order may be set in the Row and Column Chooser, but it is also possible to reorder rows in the Correlation window itself by dragging and dropping. To drag and drop a row to a new position in the order, click and drag on any of the cells in the row. The row becomes dragable and will be grayed with a dotted line around it. Drag the row to its new position.

info icon If rows are sync'd with the Groups tool, drag will not be available. Clicking and attempting to drag will merely resize the row height.

Click and hold the mouse button down on any row header and the row can be dragged to another position in the order.

Groups Order

Keeping a consistent order can be helpful if you have a large number of groups and are using another tool in conjunction with Correlation that keeps them in the Groups tool order. Choose SettingsSettings button on the Correlation Tool> Groups Order. This option orders the groups that you have chosen in the Row Column Chooser or by dragging and dropping. It does not sync the rows or columns with the Groups Tool. See Syncing Rows and Columns with the Groups Tool.

Correlation Order

Choose SettingsSettings button on the Correlation Tool> Correlation Order. The matrix is rearranged so that similar rows and columns are closer together.

Selecting Documents

Clicking a cell in the correlation matrix makes that cell's members the Current Selection. The selected cell in the matrix will be highlighted green. The Correlation Tool honors the same hotkeys as other visualization tools for selecting items from a visualization. The selection highlight in Correlation is responsive to changes in the current selection made elsewhere in IN-SPIRE.

Selection highlights in Correlation will also change if:

To Select All Documents in a Row or Column, click on a row label to select all cells in that row. Similarly, clicking on a column header will select all cells in that column.

info You can read selected documents in the Document Viewer and see their relationships to each other and to unselected documents in the Galaxy.

Tailoring the View

Comparing Absolute Numbers

By default, the height of the histogram bars in Correlation cells is proportionate to the cell in the matrix that contains the largest number of documents. To the left of every row is a color bar that is the color of the group to which the largest cell belongs and the number of how many members are in that cell.

Comparing Proportions Rather Than Absolute Numbers

When the number of documents per cell varies greatly, if cell contents show absolute numbers it can be difficult to compare cells having just a few members. Instead, compare the proportion of documents in the cell to the number of documents in the row, so that the number of documents in the row group determines the bar height rather than the largest group in the whole matrix. Choose SettingsSettings button on the Correlation Tool> Normalize.

The vertical color bar at the left of each row changes to the row group color and the number on that bar shows the number of documents in the row group.

In the image above, the cell that has 9 members is the largest. Of the several cells having that number, the first one encountered when the matrix is computed is KGB x Best.

Seeing How Many Documents Are in Each Cell

A label showing the number of documents in each cell will be visible by default in cells large enough to accommodate it. Turn these labels on or off by choosing SettingsSettings button on the Correlation Tool> Document Counts.

Adjusting the Cell Size

To adjust the cell size to fit in the Correlation window, choose SettingsSettings button on the Correlation Tool> Optimize Cell Size. The height and width of the cells in the matrix will be adjusted to be as large as possible while showing as many cells as possible in the window.

Using Shortcuts to Save Rows, Columns, and Their Order

Shortcuts enable you to save the row groups, column groups, and their order. Shortcuts that are supplied are: Save As, Manage Shortcuts, and Switch Rows & Columns. Save As allows you to save this correlation with a Shortcut Name. Manage Shortcuts allows you to Load, Rename or Delete saved shortcuts. Switch Rows & Columns exchanges the row groups with the column groups and vice-versa. .