  A formalism is developed to calculate the bubble nucleation rate in theories
where the symmetry breaking is by radiative corrections. Although to leading
and next-to-leading order the result can be expressed in terms of the effective
action of the theory, this is not true of the higher order corrections. In
particular, the imaginary part of the effective potential does not explicitly
enter the calculation and the problems of interpretation which it would entail
are avoided. Based on a talk given at the NATO Advanced Research Workshop
Electroweak Physics and the Early Universe, Sintra, Portugal, March 25, 1994
