The choice of the method of how different behaviors may be observed and categorized is considered to be one of the most difficult decisions that have to be made by a professional psychologist. Flanagan (2005) admits that such difficulty is caused because get used to think about human behavior as something continuous and seamless instead of consider it as a particular system of behavioral components. As a rule, observations have to be conducted in the early stages of an assessment process and remain to be informal in order to see how a child behaves in an ordinary environment without some disturbing factors (Weiner, Freedheim, & Graham, 2003). Unfortunately, it is not always possible to choose the most appropriate and easiest methods of observations, this is why the psychologists try to consider their opportunities and knowledge and define the behavioral peculiarities before the observational process. Current discussion offers two examples of a behavior: one is conducive for continuous measurement (a child with ADHD that can be easily distracted and cannot focus on one task for a long period of time), and another is conducive for sampling procedures (several children attend a concert with a teacher and demonstrate different reactions before, during, and after the event). The first example is focused on a child, who suffers from ADHD and cannot meet the expectations of his parents and teachers. On the one hand, it is easy to involve a child in different activities within a short period of time and prove the urgency of the chosen activity. On the other hand, it is hard to explain how and why it is necessary to behave and follow the rules. To observe the peculiarities of the child’s behavior, it is necessary to become a participant in a class and avoid the cases of reactivity as the child should demonstrate his true intentions. If an observer comes for the first time, the child may be disturbed by this fact and does not show his true behavior and reactions. This is why it is necessary to get the child used to a person and his/her presence. As soon as the observer is a regular visitor, it is possible to record and analyze this kind of behavior. The second example deals with a group of children, who visit a concert with their teacher in order to get additional information and impression on a subject. As this group is the adolescent students, they can easily record their behavior independently and share their own emotions before, during, and after the event. The description of the event should take place at first to provide the psychologist with a solid background about the event and students’ expectations. Then, students may share their own thoughts and suggestions about the concert, its role in their educational process, and its overall effects. Such observational system may be regarded as unreliable as it is based on students’ emotions and attitudes only, still, it may be considerably improved if a psychologist uses another method (event-sampling observation) insensibly and visit the same concert anonymously in order to study the duration, frequency, and intensity of the behavior (Ostrov & Hart, 2013). In this case, the chosen observational system will be effective and all-rounded. Students demonstrate different types of