Abstract:

The article describes the results from а conducted research study focused on the assessment of the teachers' computational thinking skills through criteria for learning programming concepts in Scratch. Scratch is software that could be used to program interactive stories, games, and animations and share all the creations with others in the online community. The researcher concluded that “… teachers can develop computational skills and create educational resources when using block-based programming environment for their level of experience.

Introduction:
The quality of education is extremely important for the successful realization of teachers. It influences their development as professionals and the need for continuing education and training. These circumstances oblige to apply established approaches for the formation of information and communication competence, which should solve specific and diverse problems and create preconditions for building basic competencies in different fields of science.

Assessment criteria for learning programming concepts in Scratch:
The Denner's (2012) criteria were used to assess computational thinking skills of the teachers. It defines the categories of programming concepts that can be taught in Scratch: Programming concepts; Code organization; Usability.

Methodology of the study:
Research Design:
This study was carried out in explanatory sequential mixed methods. In this research design, researchers collected quantitative and qualitative data sequentially. “The rationale for this approach is that the quantitative data and results provide a general picture of the research problem; more analysis, specifically through qualitative data collection, is needed to refine, extend, or explain the general picture”

Data sources used in the study:
- Documents
- Questionnaires
- Tests
- Semi-structured interview
- Observation

Participants:
The number of primary school teachers is 50 and the number of master teachers is 40.

Results:
- Assessment of the teachers' digital skills:
This part of the study was conducted through qualitative analysis. The results of the questionnaire for establishing the digital competencies of the participants were examined with a descriptive method for calculating the average values.

- Assessment of teachers' prior knowledge about CT:
The interpretation of the statistics for comparison of the preliminary knowledge of the two studied groups (Teachers and Masters-teachers) about CT was performed with T-TEST for independent samples.
The results show a difference in the prior knowledge of the learners from the two groups. This is a reason to perform only intragroup comparison.

- Assessment of the teachers' knowledge about CT in the end of the training:
The paired-samples T-test is used when there are two samples that are interconnected in a certain way. The null hypothesis H0 is tested by Student's t-statistics.

- Establishing the teachers’ opinion about Scratch.

- Assessment of the teachers’ work according to the criteria for learning programming concepts in Scratch:
A system of tasks based on certain criteria is used to assess the computational thinking skills. It defines the categories of knowledge that can be taught in Scratch:
1) Basic concepts;
2) Organizing the code;
3) Usability.

Keywords:

Scratch, computational thinking, assessment, programming concepts