Variable

A variable describes the data.

Operations

Add variable to View

This operation adds or updates a derived variable in a view for each selected variable.

Categorize this variable to another

This operation adds or overwrites a variable in a view and allows to recode its values.

Categorize another variable to this

This operation maps another variable’s values to the current variable categories.

Custom derivation

Derive a variable by editing its derivation script manually.

Remove

Removes the variable from the table.

Properties

This section displays the proerties of the variable:

Name
Entity Type
Value Type
Repeatable
Unit
Referenced Entity Type
Mime Type
Occurence Group
Index

Categories

Some variables can have categories defined. The list of categories is displayed with a summary information:

label (mapped label category attribute if this one is defined)
missing (if the category indeicates a missing answer)

Edit Categories

This operation allows the addition, edition abd deletion of a variable’s categories. Categories can also be removed or reordered by selecting one or multiple categories.

Attributes

Some variables can have attributes defined. The list of attributes is displayed with full information:

namespace
language
value

Add Attributes

Thois operation addds a new attribute. The combination of namespace and name must be unique.

Edit

To assign the attribute to another namespace, change its name or set its value. When editing multiple attributes only the namespace can be modified.

Remove

Remove the attributes.

Summary

Statistical summary of the variable:

variables with categories:
- frequency plot
variables without categories:
- histogram
- normal probability plot
- summary data: N, Min, Max, Mean, Median, etc
- frequencies of missiong and non-missing values

Script

Derived variables (i.e when the table is a view) are persisted in Opal’s embedded Version Control System which tracks all changes to a script over time. One practical use case is revising the history of changes and if necessary revert the script to a previous revision.

Script History Revisions

Each time a script is edited a new history revision is created or ‘committed’ to Opal’s version control system.

Commit Differences

Commit revisions are organized in a descending order, i.e., the latest commit at the top of the history stack. A simple ‘diff’ compares the changes between two immediate commits. Opal also offers a comparison between any revisions to the current revision.

Reverting Changes

By editing and saving an older revision, a script content is reverted to its previous version. This operation is tracked as a new revision.

Review Commit Differences

The commit differences are ordered by the oldest changes first (denoted in red) followed by the latest changes (denoted in green).

Values

Values can be displayed for a specific identifier or can be filtered to match to certain criteria.

Permissions

Specify the access rights to a particular variable and its content

View with summary Permission

Allow the user to see the variable details with its data summary. Does not allow values querying. It induces the read-only access to the parent table and datasource.