How to count a specific category in a multi select field?

Hello Airtable community,

I´m having a difficulty for finding how many times a specific category (that is in a multi-select field) appears in a table where I´m tracking specific “needs” mentioned in 1:1 interviews. How can I do?

Part B of the question (once the other part is solved)
One more thing. In the report I may have the same person more than one time and I don´t want to double count the needs, what do you recommend me to do for this?

Hi Fellows, the simplest way might be to convert the multi-select field into a ‘Link’ field, and do a rollup field with the following formula:

COUNTALL(ARRAYUNIQUE(values))

This will give you the number of times a category has been mentioned without double counting

Here’s a working version

So interesting! Thank you @Adam_C. I will try this, and see if my question was the right one for the problem I had (I was able to solve it in a Google Sheet, but I want to have my reporting where I have the information, specially because in the apps I already have the graphics for reporting…)