  In this paper, we present a non-Gaussianity consistency relation that enables
the calculation of the squeezed limit bispectrum of the curvature perturbation
in single-field inflationary models by carefully inspecting the background
evolution and the linear perturbation theory. The consistency relation is more
general than others in the literature since it does not require any specific
symmetry, conservation of the curvature perturbation at large scales, attractor
background evolution or canonical kinetic energy of the inflaton field. We
demonstrate that all known examples of the squeezed limit bispectrum in
single-field models of inflation can be reproduced within this framework.
