The article considers modern approaches to analyzing the effectiveness of interventions in relation to time, that is, the length of the period after the beginning of their application. The role of the analysis of the Kaplan-Meier curves for the evaluation of the effects of compared interventions depending on the time is discussed. Various options of the relative layout of the Kaplan-Meier curves in the course of the study are examined. The results of a recent analysis of the duration of the period between the onset of statin use and the development of clinical benefits of therapy are presented. In particular, the possibility of using the TTB indicator of intervention and TTH indicator, caused by the intervention, is discussed in making a clinical decision about the validity of the choice of a particular treatment method, in particular the indicator of number of patients Analysis of the Kaplan-Meier curves as an approach to assessing the effectiveness of therapy Modern effective clinical practice largely depends not only on the clinical experience of the physician, but also on the skills of searching and evaluating the evidence-based information that allows to choose the optimal treatment strategy. Such tactics can be determined only in the course of large and well-planned randomized clinical trials (RCTS). Analysis of the survival curves constructed using the Kaplan-Meier method has become one of the main approaches to assessing the incidence of adverse outcomes in modern clinical trials. There may be several variants of the "behavior" of such curves [1]. Such curves may not diverge throughout the study period (Figure 1A), indicating that there is no difference between the efficacy and / or safety of the interventions compared. Such curves may diverge, which will indicate a difference between the who need to be treated with a particular drug. Opinions that emphasize the importance of evaluating the effectiveness of interventions with absolute rather than relative risk of adverse clinical outcomes are mentioned. Clinical situations in which the duration of the TTB is of particular importance, in particular, in patients with a very high risk of developing complications of cardiovascular diseases (for example, after an acute coronary syndrome) and in patients who in most cases have limited life expectancy are considered. The role of atorvastatin in clinical situations is emphasized, in which the earlier achievement of the clinical advantages of lipid-lowering therapy is important. Data on the role of statins, in particular atorvastatin, are given in the early stages after the development of acute coronary syndrome.