Ask HN: Do flyers/give-away pens/tchotchkes work?

Part of our marketing involves in person interactions, typically in market-vertical conferences, sometimes in sales calls.

I'm wondering about the efficacy of spending money on printed brochures, branded pens we'd give away, and various other tchotchkes that have been proposed.

Is there any return on these things?

Our audience is primary business finance. Just about everybody else that markets to this group makes a big effort on their print and promotional materials. I'm loathe to spend the money without knowing what my real return will be.

Anyone have experience / words of advice on this?