# Optional Questions

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## Optional Questions

Optional questions are a set of questions that are displayed to the user on random, based on a probability value.

You can add one or more optional questions in each group and let the group decide which ones to display.

### Group Maximum Number of Questions

As we mentioned in a previous article, each group has a field called "maximum number of questions". This field determines how many questions of the group will be displayed to the end-user, in display order as they appear in the questionnaire design section.

### Non-Optional Questions

Starting with the non-optional questions, group will include all the non-optional questions until it reaches the max or until they run out and then start selecting from the optional questions based on their probability. A group may select 0 or more optional questions until it reaches the max value.

### Question Probability

You can mark a question as optional by setting Optional Switch to "on" and setting a probability, as it appears on the following screenshot: You can either select one of the preset values: or select Custom and fill in the probability of the question. ## How Probability Works

You can work with question probability in various ways:

• Set a fixed probability for more than one questions and select a set of them.
• Set auto probability for some or all of the questions

### Fixed Probability

You can set your question a fixed probability based on the given preset values or a custom value.

NOTE: If the number of optional questions is less than the number of questions needed to fill the group, all questions will be selected. Only questions with 0 probability will be skipped.

Normally, the probability values should sum up to 100%, but you can sum up to less than that to leave room for not selecting a question.

Example:

 Question Probability Question 1 50% Question 2 30% Question 3 10% Question 4 5%

From the above example, there is a 5% probability of not selecting any question.

With 2 questions left for the group, we could have the following steps:

1. There is 95% probability of selecting the first question
2. Select "Question 2"
3. There is 65% (95% - 30%) probability of selecting the second question
4. Select No Question

Or the following:

1. There is 95% probability of selecting the first question
2. Select No Question
3. There is 95% probability of selecting the second question
4. Select "Question 4"

With 1 question left for the group, if the sum of probabilities do not sum up to 100%, there is change that no question is selected.

### Auto Probability

You can set auto-probability to questions that you do not wish to have a specific probability but share the remaining probability equally. This allows you to:

• Have as many questions as you like, with equal probability without editing the values
• Have questions with auto probability and questions with fixed, to provide more weight

Example:

 Question Set Probability Real Probability Question 1 50% 50% Question 2 30% 30% Question 3 auto 10% Question 4 auto 10%

In the above example, "Question 3" and "Question 4" will share the remaining 20% over their count (20/2 = 10% each).

### Examples

Assume we have a group with 5 maximum number of questions:

Example 1:

 Question Optional Status Probability Selected Question (by Display Order) Question 1 non-optional - 1 Question 2 non-optional - 2 Question 3 non-optional - 3 Question 4 non-optional - 4 Question 5 optional 40% - Question 6 optional 30% 5 Question 7 optional 30% -

Example 2:

 Question Optional Status Probability Selected Question (by Display Order) Question 1 non-optional - 1 Question 2 non-optional - 2 Question 3 non-optional - 3 Question 4 optional 50% 5 Question 5 optional 30% - Question 6 optional 10% - Question 7 optional 10% 4

Example 3:

 Question Optional Status Probability Selected Question (by Display Order) Question 1 non-optional - 1 Question 2 non-optional - 2 Question 3 non-optional - 3 Question 4 optional 50% - Question 5 optional 20% - Question 6 optional 5% - Question 7 optional 10% 4

In the above example we can see that there is no question selected for no5. This is a probability that might happen if questions' probability do not sum up to 100%.

Example 4:

 Question Optional Status Probability Selected Question (by Display Order) Question 1 non-optional - 1 Question 2 non-optional - 2 Question 3 optional 50% - Question 4 non-optional - 3 Question 5 optional 20% 5 Question 6 optional 5% - Question 7 optional 10% 4

In the above example we can see that regardless of the display order, the non-optional questions will be selected first and then the optional questions.