General question- does combining the 2013 and 2014 survey make sense, given that we expect a lot of overlap (same people surveyed)?
Also, why treat EA as a latent variable when it was directly surveyed? Shouldn’t we just combine by saying if you answered Yes to an EA questions, you are EA?
It’s a quite bit more general than Lagrangian mechanics. You can extend it to any functional that takes functions between two manifolds to complex numbers.