Strong coupling, unification, and recent data

The prediction of strong coupling assuming (supersymmetric) coupling constant unification is reexamined. We find, using the new electroweak data, s(MZ)0.1290.010. The implications of the large s value are discussed. The role played by the Z quark width is stressed. It is also emphasized that high-energy (but not low-energy) corrections could significantly diminish the prediction. However, unless higher-dimension operators are assumed to be suppressed, at present one cannot place strong constraints on the superheavy spectrum. Nonleading electroweak threshold corrections are also discussed.