Is it possible to create a "diagnostic" quiz?

Hi, Jana,

Yes, that's possible. You could use variables to track how many questions the user answers correctly for each topic. Then use triggers that show the appropriate text (e.g., "You did well on Topic A!") based on the associated variables. 

This post has info about tracking custom questions that you might find helpful:

https://community.articulate.com/discussions/articulate-storyline/tip-track-responses-to-custom-questions-or-surveys 

It's worth it to learn about variables and conditions, because they provide the real power in Storyline. Here's some User Guide info to get you started:

• https://community.articulate.com/series/articulate-storyline-360/articles/storyline-360-working-with-triggers#conditions 
• https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-work-with-variables