Note: This post was written quite quickly and I'm not well versed in this subject matter. 

Thomas' paper here and Dylan Matthews' excellent write-up on it here.

I would love to spark some discussion on this: total factor productivity growth being linear in many developed countries, not exponential, could potentially be very scary.

Of course, as Dylan mentioned, TFP has issues. I believe the main critique is that, due to its simplicity, it can sometimes remain the same even after changes in technology and productivity.