A method for planning of experiments has been elaborated which makes it possible to decide the adequacy of the two-parameter model of binary copolymerization. At the same time, the procedure provides equal and reasonably low relative errors of r1and r2. In the approximate knowledge of the parameters and of the value of analytical error, the procedure furnishes the number of measurements and the monomer feed values necessary for the desired accuracy. It was obtained as a “rule of thumb” that, in spite of the erroneous practice, the points should be arranged uniformly within the range of copolymer composition instead of monomer composition. For the objective performance of retrospective evaluations, an “efficiency factor” has been introduced.