factor "Types of testing". Based on the data obtained during the iteration, a model of the priority influence of factors on the quality of software testing is synthesized. The factor with the highest priority is located at the top of the model, and the one with the lowest are at the bottom. Factors with the same priority are on the same level. The model of the priority influence of factors is detailed with the help of the causeandeffect diagram of Ishikawa, which is a graphical arrangement of the factors influencing the object of analysis. The priority of the factors is positioned from right to left from the "head" to the "tail of the fish skeleton".