Interviewing Options Traders

I’ve interviewed a lot of junior candidates over the past few years and noticed something consistent. Many can explain options from a theoretical pov (Black-Scholes etc). But when you push past that, it thins out fast... like they struggle to answer questions such as How does a short strangle behave when skew steepens aggressively? What actually happens to margin when you roll short premium in a vol spike? Why is a risk reversal often more of a volatility trade than a directional one? What changes when you move from a low IV regime to a structurally high one? That’s where conversations start to stall. It makes me think we don’t really have a clean signal for applied derivatives competence. Own trading records maybe? but those are hard to verify and easy to cherry-pick... Tbf I have recently seen candidates with the Certified Futures and Options Analyst (CFOA) credential who do tend to do better in those areas but aside from that, if someone says they want to work in options or volatility trading, what would you actually want to see as proof they understand the mechanics? (Not just theory, but mechanics and strategy.)