Supersymmetry and R(b) in the light of LEP 1.5

We re-examine the possible magnitude of the supersymmetric contribution to R(b) equivalent to Gamma(Z(0) --> (b) over bar b)/Gamma(Z(0) --> all) in the light of the constraints imposed by the absence of light charginos at LEP 1.5, implementing also other available phenomenological constraints. We find the supersymmetric contribution to be R(b)(susy) < 0.0017, and discuss the extent to which this upper bound could be strengthened by future constraints on the chargino and top-squark masses. Such values of R(b)(susy) tend to disfavor a supersymmetry explanation of the apparent R(b) discrepancy.