About codelists and codelist items

Codelists enable you to design items in which a user selects from multiple choices. A codelist is a collection of code-label pairs that gather together the entry choices for an item. A code-label pair consists of a single code (the value that is used for analysis) and a label (the value that is visible to users). Each code-label pair makes up a codelist item.

Certain properties of codelists and codelist items must be unique:

• Code of a codelist item—Must be unique within a codelist.
• Label of a codelist item—Must be unique within a codelist.
• RefName of a codelist or codelist item—Must be unique within study object type.
• Title of a codelist or codelist item—Must be unique within a codelist.

You can include a codelist in the definition of a float, integer, or text item, and the Yes No item type includes a predefined codelist that contains Yes and No options. When you create a codelist, specify whether a study user must select only one option or can select multiple options.

Codelist data can appear as a drop-down list, as a set of radio buttons, or as a set of checkboxes. You specify the formatting information when you generate the layout of the form or item containing the codelist.

Codelists and conditional item relationships

If you want to design more complex items in which a user both selects one or more options and provides additional information about the selected option or options, you can make an item conditional on an option in a codelist. You can use conditional relationships for collecting:

• Nested levels of multiple-choice data.
• User-entered information along with multiple-choice data.