  BCS theory accounts for the pairing instability in the weak coupling limit,
but fails to describe pairing fluctuations above $T_c$. One possibility for
describing these fluctuations in the dilute limit is the T-matrix
approximation. We critically examine various degrees of self-consistency in the
T-matrix formalism, along with a non-diagrammatic two-particle self-consistent
(TPSC) formulation, in the strong coupling regime, where an exact solution is
readily available. We find that one particular degree of self-consistency is
quite accurate, particularly at low temperature as evidenced by examining both
static and dynamic properties.
