Do you make more watts in the big ring?

On a lot of my training rides, in particular when it's windy, I'll stay in my middle ring to have a little tighter gear ratios.  My buddy sez that's OK for training rides, but that one should always be in the big ring in a race because you're going to make more watts even if the gear ratio is the same.  I'm thinking that since 39/14 is the same as a 53/19 for all intents and purposes, power output should be exactly the same at the same cadence.  Anyone with a power meter wanna test this theory out?