**3. Study**

### **3.1 Project and sample**

The study presented in the chapter was conducted as part of the unique International Survey of Children's Well-Being – Children's Worlds (ISCWeB, https://isciweb.org/), which today involves more than 40 countries around the world. The project has existed for more than 10 years, during which three waves of data collection have been completed. The mission of the project is to collect representative data on children's lives and daily activities, their pastimes, and their perception of their well-being in as many countries as possible in order to raise awareness and improve the well-being of children and their lives.

The organizers and participants of the project called for the voices of children themselves to be heard, giving children the opportunity to express their views on various aspects of their lives and well-being, because "in an era of information, it is surprising to discover how little we know about the state of our children" [8, 9].

Researchers from more than 40 countries are currently participating in the project. The third wave of the project (2016—2019) involved scientists from 35 countries from four continents, who analyzed the performance of more than 128,000 children

of three age groups – 8, 10, and 12 years old [10]. Russia first joined the project in 2016, presenting the results of the well-being of 10- and 12-year-old children from the Tyumen region. The Tyumen region is the largest region and ranks 3rd among all the subjects of the Russian Federation. In recent years, the Tyumen region has consistently been included in the list of leading regions in the country in terms of the level and quality of life. Accordingly, the results of the presented study do not reflect the general picture of the subjective well-being of children in the country as a whole.

In total, 1904 children from 24 schools, nine cities, and five rural settlements took part in the study in the Tyumen region. The study sample consisted of 953 10-yearold children: 437 (45.9%) boys, 516 (54.1%) girls; and 951 12-year-old children: 478 (50.5%) boys, 473 (49.7%) girls. In the total sample of two age groups, boys comprise 48.1% (N = 915) and girls 51.9% (N = 989).
