A factorization theorem is demonstrated for special types of contributions to the time‐dependent collision operatorG00(&tgr;) which plays a central role in the classical master equation derived by I. Prigogine and P. Re´sibois; this theorem expresses the mutual independence of two subgroups of particles when these groups are noninteracting with each other during a given time interval (&tgr;i, &tgr;j) of the collision process. The theorem is applied to rederive in a very direct way the kinetic equation of an homogeneous stable plasma, obtained first by R. Balescu. Other possible applications of the method are also discussed.