SUMMARY
Effective design and implementation of distance learning systems requires the use of their appropriate analysis. In the article it is identified system-forming factors at different stages of their life cycle based on the analysis of theoretical and experimental studies of distance learning systems. There are considered the approaches to the formation of a list of system-forming factors, determination of the hierarchy and interrelation of these factors, the experimental determination of the quantitative indicators of influence of separate factors on productivity of the distance learning system. It is noted that the accounting of systemforming factors will contribute to the creation of effective systems of distance learning. It is proposed a creation of an adaptive learning environment that can self-modify, in accordance with the stated objectives.