In CommCare HQ the answers to multi-select questions are stored as a space separated list e.g. "item1 item2 item3". Exporting this raw data to to Excel or a CSV file makes it difficult to analyze so CommCare provides the user with the option so split the multi-select answers into multiple columns. The exported data would then look as follows:
Assuming we had two forms with the following values:
Form Submission 1 - question1 = "item1 item2 item3"
Form Submission 2 - question1 = "item2"
The exported data would look like this:
|question1 | item1||question1 | item2||question1 | item3||question1 | extra|
A '1' in the cell indicates that the choice was selected, and a blank cell indicates that the choice was not selected.
Any choice that was not selected when the custom report was configured, or deleted choices from prior application versions, can be found in the "extra" column.
On the CommCare user interface this is configured when creating or editing a custom export by selecting the "Expand Multiple Answer Questions" option.
Please note that in case exports, this concept is achieved through the 'Type' column. If the corresponding dropdown for a property in the type column is changed from plain to 'multi-select,' you can split a property created by a multi-select question into its constituent parts.