The condition for gauge coupling unification at one loop is whether the following expression is satisfied \frac{\alpha^{-1}_3 - \alpha^{-1}_2}{\alpha^{-1}_2-\alpha^{-1}_1} = \frac{b_{0\,3} - b_{0\,2}}{b_{0\,2} -b_{0\,1}}.
Remarkably, this is precisely satisfied to experimental errors in the values of \alpha^{-1}(M_{Z^0}).