  We consider the conditions for integrating out heavy chiral fields and moduli
in N=1 supergravity, subject to two explicit requirements. First, the
expectation values of the heavy fields should be unaffected by low energy
phenomena. Second, the low energy effective action should be described by N=1
supergravity. This leads to a working definition of decoupling in N=1
supergravity that is different from the usual condition of gravitational
strength couplings between sectors, and that is the relevant one for inflation
with moduli stabilization, where some light fields (the inflaton) can have long
excursions in field space. It is also important for finding de Sitter vacua in
flux compactifications and KKLT scenarios, since failure of the decoupling
condition invalidates the implicit assumption that the stabilization and
uplifting potentials have a low energy supergravity description.
  We derive a sufficient condition for supersymmetric decoupling, namely, that
the Kahler invariant function G = K + log |W|^2 is of the form G = L(light,
(heavy)) with H and L arbitrary functions, which includes the particular case G
= L(light) + H(heavy). The consistency condition does not hold in general for
the ansatz K = K(light) + K(heavy), W = W(light) + W(heavy) and we discuss
under what circumstances it does hold.
