I am working on a pre-analysis plan and have to specify what I am going to do with outliers. I have two categorical variables (5 levels and 2 levels) and I will be performing a chi-square test for independence.

I thought of using a boxplot to detect outliers, but now I am not sure if it is even possible to have outliers in categorical data. You have such a small range, so a lot of variation in the data won't be possible. The only outlier I could think of is wrong data (data which falls outside the possible range due mistakes). I have looked online and in my statistic books, but was unable to find a solution, so I really hope someone here can help me out.

To summarize, is it possible to have outliers in categorical data and if yes, how do I detect them?

Thank you so much for your time and have a nice day!