A method of optimizing one or more parameters in a process for considering a DNA containing sample using a method of modeling and a method of modeling itself are provided. The method of modeling the process for considering a DNA containing sample uses a graphical model. The model seeks to provide one or more optimized parameters for the consideration process. The methods aim to consider the whole process, for instance, the number of cells required for the process and/or the extraction efficiency and/or the sub-sample volume relative to the sample volume and/or the amplification efficiency and/or the optimum number of amplification cycles and/or the effect of degradation on the amount of amplifiable DNA in the sample.