The paper considers the dynamic and informational properties of intelligent systems. The relationship is established between control quality and stability in such systems. The method was developed and a study was conducted of the dependence of the control quality and the time spent by the human operator on the evaluation of the test image. The influence of the clean delay time on the stability margin and the quality of the setting process is studied. The study shows that in intelligent systems that work in connection with a human-operator (a group of people) or independently, the time spent (a latent period) to implement thinking forms affects on the one hand the control quality, on the other the system stability. The desired value clean delay time is set. The research results are presented. The new parameter of information properties of intelligent systems has been introduced - the control quality. © 2021 Elsevier B.V.. All rights reserved.