Abstract
We compute the supersymmetric contribution to
R
b
≡Γ(Z→b
b
¯
)/Γ(Z→hadrons)
in a variety of supergravity models. We find $R^{\rm susy}_b\lsim0.0004$, which does not shift significantly the Standard Model prediction
(
R
SM
b
=0.2162
for $m_t=160\GeV$). An improvement in experimental precision by a factor of four would be required to be sensitive to such an effect.