The work distinguishes two types of complex systems: "real systems" and "virtual systems". The first ones are the object of computer science research, and the second ones are the object of software engineering. The latter include software systems (SS) and the software development process (SDP), which is the object of scientific work research. SDP refers to goal-oriented systems. In such systems, on the basis of the set goals, the task of synthesizing their structure (individual elements and the relationship between them) arises, which is aimed at achieving the set goals related to the quality of SDP. It is believed that the success of SS development directly depends on the quality of SDP. The work considers the problem of assessment and improvement of SDP on the basis of two maturity models: SMMI, SPICE. Both models use a point scale of the first type, when the assessment is made according to objective criteria, so that individual assessments are some fluctuations of the real values. At the same time, there are generally accepted standards that correspond to the gradations of the point scale. The main component of the SMMI model is the focal area, which is characterized by the "level of opportunity" on a point scale from 0 to 3. The main component of the SPICE model is a process characterized by a "level of possibility" on a point scale from 1 to 5. For the discrete version of the SMMI model, the concept of "maturity level" is used, thanks to which the quality of the SDP of the entire IT organization is assessed. The formalization of the model was carried out and static and dynamic planning models of the SDP of the IT organization have been implemented, which are integrated into a single technology of "sliding" planning. One of the main disadvantages of the discrete version of the SMMI model is that it does not take into account the specifics of the IT organization activity. On the other hand, the SPICE model does not allow for the assessment of the entire SDP of the IT organization. Therefore, a synthesis of a discrete maturity model based on the SPICE reference model was proposed. Its main goal is to minimize the main drawbacks of the SMMI model. For this purpose, the use of utility theory was proposed. A hierarchical structure of criteria is formed, on the basis of which the utility function is synthesized. Previously, at the level of a separate process, the SPICE model was formalized and the structure of the utility function was determined on this basis. Taking into account the fundamental properties of the systems, the trend of its change based on the used resources is presented. Next, the experts compare the characteristics of the processes of the SPICE model and the IT company from the point of view of the importance of the processes for increasing the level of maturity of the SDP. This information from the experts is provided to the analysts, who place the processes in a queue depending on the importance from the point of view of the utility function.