Searching for stages of teacher's skills in assessment

•A framework for measuring teachers’ skills in using various techniques of assessment is proposed.•Development and validation of an instrument to measure teachers’ assessment skills is discussed.•Teachers’ assessment skills are grouped into four stages of assessment behaviour, which move from skills associated with everyday routines to differentiation in assessment.•Teachers situated at higher stages are more effective in promoting student learning outcomes.

This study investigates teachers’ skills in using various techniques of assessment in mathematics by taking into account the four phases of assessment and the five measurement dimensions of the dynamic model of educational effectiveness. A questionnaire measuring assessment skills was administered to a 10% sample of Cypriot teachers (n = 240) and a high response rate was obtained (74.2%). Semi-structured interviews provided support for the internal validity of the study. Assessment skills are grouped into four types of behaviour which are discerned in a distinctive way and move gradually from skills associated with everyday assessment routines to more advanced skills concerned with differentiation in assessment. Teachers implementing more advanced types of assessment behaviour have better student outcomes. Implications of findings are drawn.