Within Teamwork Desk, it is possible to view the failed searches that users have attempted but have not returned an answer.
This report shows you searches which users have attempted and have not returned an answer. It gives a great insight to improvements/additions that need to be made to your existing Docs.
There are two recommended options that you can use this for.
We have a keyword feature available for Docs, where you can enter in specific terms that will then be associated with that Doc. So when they next search for it, the Doc will also be displayed.
The Keywords tab is available when editing/creating a Docs page:
You can use the words that customers are using which are returning failed results as keywords which when searched again will now link to that doc:
Having these searches available, may help you identify areas where new Docs are needed. So if you see that users are continuously searching a specific word/question, it might be time to create a new Doc based upon this.
For more information see: Getting started with helpdocs