Data Concordance

Overview

Colectica allows you to describe how variables measure the same information at different times or among different populations.

Metadata Structure for Variables

Colectica uses three levels of items to describe how variables from different points in time or different datasets correspond to each other.

Item Type	Description
Variable	A column in a dataset
Represented Variable	Describes how a variable is measured; the data type. This may be consistent across rounds, or may change.
Conceptual Variable	Describes a measurement of a person, firm, or other thing, without specifying the data type. The most generic way to describe something that is measured.

Consider a dataset that measures marital status in three different years: 2000, 2005, and 2010. The dataset may look like:

ID	marstat2000	marstat2005	marstat2010
1	Married	Divorced	Married
2	Divorced	Divorced	Divorced
3	Married	Married	Widowed

In the first two years, the data was represented by two choices: Married and Divorced. In the third year, the data contain a new option: Married, Divorced, and Widowed. Two different representation types are used for this variable over time.

This dataset can be documented with three variables (aside from the ID): marstat2000, marstat2005, marstat2010. Since a variable corresponds to a single column in a single data file, three variables are necessary.

Since there are two representation types, we will use two represented variables; let’s call them marstat and marstat-plus.

Finally, a conceptual variable is used to describe the common information among the three variables. This can be named marstat, and should be referenced by both the represented variables.

The following diagram visualizes these items and their relationships.

Variable Concordance Views in Colectica Portal

By specifying the variables in this way, Colectica Portal is able to create concordance views that show a comparison the variables.

For coded variables, Portal can also show a comparison of the codes used for each variable.

Describe Concordance in Colectica Designer

To assign a represented variable to a variable:

1. Navigate to the variable editor for the variable.

   

2. On the Concept tab, search for a represented variable to assign, or create a new one.

   

   See also

   For instructions on assigning or creating the represented variable, see Reference a Single Item.

3. Assign the same represented variable to any other variables, as appropriate.

4. Drill into the represented variable.

5. Using the represented variable’s editor, assign or create a conceptual variable.

6. After assigning represented and conceptual variables, you can view the list of all referenced variables by using the Links view from the represented variable.