I was recently arguing with a college about a concept in economics and was told that my approach is invalid because it based on theory/method developed from the 1980 and that current methods don't approach the problem the same way.
I cited my sources from a credible source which was published (NBER to be specific) however to him it was a good enough of a counter argument to invalidate my point. He did cite contemporary research which approaches the problem differently however he didn't address the sources I brought.
This isn't the first time I've heard the argument from my peers and I'm wondering if the "in with the new out with the old approach" is a general approach taken in academia.
Is the fact that a certain paper or theory is old or dated enough to invalidate it?