From LimeSurvey Manual
Matrix Filter (array_filter)
The Array filter setting allows you to use any multiple choice question to select or set which responses are displayed in a subsequent list, array or multiple choice question.
- Multiple choice
- Multiple choice with comments
- Multiple short text
- Multiple numeric
- Array (5 point, 10 point, Yes/No/Unknown, Increase/Same/Decrease, Column)
- Array (Dual Scale, Text, Numbers)
Furthermore, each of these question types can be filtered.The only exception is Array (Column), which can filter other questions, but not itself.
How to set a filter
To set a filter, enter the question code of a multiple options question in the array filter box of the question you are currently editing. The respective question will be used as the source of information for the current question, the selected answers from the previous question being retrieved and used as answer options for the current question. For example, if your source multiple option question code is "Q1", enter "Q1" into the 'Array Filter' box to start the filtering process of the answers. Only the answer options that are selected in question Q1 will be visible in the array_filter-ed question.
The selected options can be displayed in cascade. This means that you can select a question which filters another question, which filters another question, and so on.
Matrix Filter Beispiel
Let's take a look at the following example to better understand the power of this setting:
In the screenshot from above, we got two questions. The first one is a multiple short text question type, while the second one is an array dual scale question type. The answers you provide in the first question will be listed in the second one. Technically, the answers you provide to the subquestions from the first question are filtered and displayed in the second question.