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Hello,
Is it possible to limit the number of times a participant chooses a specific option?

Specific Example: Can I limit how often the option "Don't know/can't say" be chosen in a radio button/array type of question, to say, 25% of the total number of questions? e.g., if there are 100 questions, the participant cannot choose "don't know/can't say" more than 25% of the time.

Thanks in advance!

If all are in the same question, use a question validation equation with the countif() function.

- www.limesurvey.org/manual/ExpressionScri...#Access_to_functions

Thank you!

I am not a coder, but willing to try my hand and experiment. Is there any place that teaches how to write this code?

Just enter in the "question validation equation"  an equation that has to be TRUE.
In your case the number of "DK/NA" answers is less than 25% of the number subquestions.

So: countif(...)<xx 

in a radio button/array type of question

e.g., if there are 100 questions

But as I cannot imagine that you want the respondents to answer 100 subquestions in one array, there will be subquestions be hidden by relevance equation.
So you have to count the displayed subquestions.
Best you use the property ".relevanceStatus" and sum it, like
{sum(self.relevanceStatus)}
Now you have a dynamic function to calculate the 25%
ceil(sum(self.relevanceStatus)*0.25)

So you can validate that the number of "DK/NA" that you get by the countif-functions has to be less than this calculated limit of 25%.

countif("6",self.NAOK)<ceil(sum(self.relevanceStatus)*0.25) 

About this, read
[url] www.limesurvey.org/manual/Question_type_...28em_validation_q.29 [/url]

[url] www.limesurvey.org/manual/ExpressionScri...mplemented_functions [/url]

[url] www.limesurvey.org/manual/ExpressionScri....22that.22_variables [/url]

Thank you! 100 was just an example, it is likely to be closer to 30 or 40. I shall read up the resources provided too. Appreciated!