The only time I’ve been asked to do whiteboard puzzles on-the-spot I bombed so terribly that they didn’t even get back to me.
On the hiring side, having a conversation with someone about the actual work they’ll be doing has yet to fail me. It’s obvious if they know their stuff.
And why “I want to see how you think” approaches to interviewing (whiteboards, brain teasers) are so bad at identifying talent. If you gave Gaiman a prompt and watched him write while you asked “what are you thinking now?” for 30 minutes, you’d come away believing he’s terrible.