In the global development towards inclusive education, more and more diversity within classrooms is expected. Teachers and school leaders choose to group pupils according to different variables, homogeneous on abilities of heterogeneous, so-called mixed-ability groups. In research ‘mixed-ability grouping’ means grouping by academic ability (For example Askew, 1995; Barker, 2003; Zakelj, 2013). In this study, we focus on grouping by educational needs among other variables such as age and academic level. We define a mixed-ability group as Grouping pupils mainly by assessing their educational needs. In the mixed-ability groups, the educational needs of the pupils vary, especially on the level of learning and development, social-emotional functioning, and communication (de Boer & Tenback, 2021). One can imagine that teaching such a mixed-ability group is a challenge for the teaching staff. In order to maintain a positive class climate and to ensure pupils feel included, teaching staff needs positive attitudes and a positively developed self-efficacy.

This study is conducted in the Netherlands, where we see these kinds of mixed-ability groups within schools for so-called specialized education. Different kinds of special education work together to integrate pupils and teaching staff in order to become an integrated school. We recognize this development as a step towards more inclusive education for all. Studying this development helps us to gain more insight into attitudes and self-efficacy of teaching staff within integrated schools and gives us a better understanding of the diversity within these classrooms, the benefits, and pitfalls according to the teaching staff, and the experienced class climate and perception of inclusion by the pupils. We try to answer the following research questions:

• What is the attitude and self-efficacy of the teaching staff of the mixed ability groups?
• What are the benefits and pitfalls of the mixed ability groups according to the teaching staff?
• How do the teaching staff estimate the educational needs of the mixed-ability group?
• Is there a relationship between the teaching staff's estimated educational needs of the mixed-ability group and the attitude and self-efficacy of the teaching staff?
• Which intensity of educational needs does the pupil of the mixed ability groups have, how do they experience the class climate, and what is their perception of inclusion?
• Is there a relation between the educational needs of the pupils of the mixed-ability group and their experienced class climate and perception of inclusion?

This study is part of a broader longitudinal study on integrated schools and is financed by The Netherlands Initiative for Education Research (NRO) (project number: 405-18-750). Six schools participated from all over The Netherlands. Sixty-six teaching staff members were included, including 48 teachers and 18 teaching assistants. They were asked to fill in a survey to measure attitude, self-efficacy, and the estimated educational needs of their group. The teaching staff was also interviewed to learn about the benefits and pitfalls of working with mixed-ability groups. Pupils in the age group 5-11 years were asked to fill in a survey in a one-on-one situation (N=169). We used adapted versions of the Perception of Inclusion Questionnaire (Zurbriggen, Venetz, Schwab, & Hessels, 2017) to measure the perception of inclusion of the pupils, and the Classroom Peer Context Questionnaire (Boor-Klip, Segers, Hendrickx, & Cillessen, 2016) to measure class climate. Files of the pupils were used to gain insight into their educational needs. Data from the second measurement were used.

These are preliminary results. At the ECER conference, we will present the final results. The teaching staff has neutral to positive attitudes towards inclusion and integration (M=3.36, SD=.30). The self-efficacy of the teaching staff is also positive (M=4.04, SD=.27). Teaching staff considers the abilities of pupils to learn from each other as a benefit of the mixed-ability group. They talk about the opportunity to gain access to more expertise from different types of (special) education as an important benefit of working with mixed-ability groups for themselves. For parents is the benefit of mixed-ability groups that they do not have to choose a specific type of education. The pitfalls are considered the well-being of vulnerable pupils, and the pressure on teaching staff to cope with a wide diversity of pupils. The teachers estimate the educational needs of the group as “on a regular basis” to “intensive”. This means, that the pupils overall need a lot of near attention from the teaching staff. Overall, we see a negative relation between the estimated intensity of special educational needs and the attitudes of the teaching staff. The pupils need the most support in the domains of learning and development (M= 4.4, SD= 1.0) and social-emotional functioning (M= 4.3, SD= 1.0). Pupils experience the class climate as positive (M = 2.43, SD =.32), and their perception of inclusion is also positive (M = 2.67, SD =.43). We do not find any relation between special educational needs, experienced class climate, and perception of inclusion.

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