Education for all in action: Measuring teachers’ competences for inclusive education

Table 1. (Continued) original scale-name Item Nr To what extent are you able to. . .? / Do you agree with . . .? Decision after step 1 Reason for decision Decision after step 2 Reason for decision Final scale-name Beliefs on the responsability of the educational field to create EfA, focused on collaborating with parents & colleagues C5.01 Make parents from different backgrounds feel comfortable about coming into school. stem changed from "it is my job to. . ." to "To what extent are you able to. . .?" skewed distribution / ceiling effect collaborating with parents C5.02 Help parents to support their children to do well in school. C5.03 Involve the parents of students with special needs in their children’s educational career. C5.04 Adapt the way you communicate with different kinds of families (e.g. single parents, LGBT+ parents, non- native speakers. . .). C5.05 Empathize with the situation and motivations of different parents. delete suggested by modification indices C5.06 Use the insights that parents give you about their child. C5.07 Establish a good relationship with all parents, even if you do not like them. C5.08 Actively make time for parents who want to have a conversation with me. delete suggested by modification indices C5.14 Always be available for questions from parents during school hours. C5.15 Allow parents to give some input about my lessons. C5.09 Consult other professionals (e.g.: SEN teachers, speech therapists, . . .) when one of your students has extra needs. delete suggested by theoretical interpretability, r-square

values and factor loadings collaborating with colleagues C5.10 Involve the school team (e.g.: teachers, student counselor, . . .) when one of your students has extra needs. delete suggested by modification indices, r-square values and factor loading C5.11 Integrate lesson ideas from colleagues into your own teaching practice. C5.12 Ask colleagues for feedback to improve your teaching. C5.13 Create new teaching methods or materials together with colleagues in order to support students with learning difficulties. C5.16 Share learning materials with colleagues that meet students’ different learning profiles. delete suggested by r-square values and factor loadings Ethnic minorities C6.01 The school should provide specific services for students who want to follow religious practices (e.g., prayer room, halal/kosher food). Ethnic minorities Beliefs on the responsability of the educational field to create EfA, focused on C6.02 The school must allow students with a migration background to speak a language other than Dutch at school. C6.03 As a school, you should not take into account the fatigue of Muslim students participating in Ramadan. delete low correlations with other items C6.04 The school library should have books in the different home languages of the students. C6.05 It is important to encourage students of immigrant origin to be proud of their ethnic and cultural background. C6.06 As a teacher, it is your job to react to racist statements by students. delete low correlations with other items

Disability C6.07 It is time that we give children with a disability a full place in mainstream education. It is their right. Disability C6.08 It is sensible to not send students to special educational support too quickly. C6.09 The school’s infrastructure must be made accessible at all levels to people with physical and sensory disabilities (vision, hearing, motor). C6.10 You cannot expect the teacher to meet the needs of a child with a disability in mainstream education. C6.11 It is normal to prepare extra tasks for students who work at a higher or lower level. delete low correlations with other items SES C6.12 The influence of a teacher is limited compared to the influence of the pupil’s home environment. delete part of scale with low cronbach’s alpha General policy C6.13 Teachers must be capable of working with students from different home situations. C6.14 Students from families with financial problems should be provided with appropriate support (e.g. payment plan, special support fund for students who cannot pay the school fees). C6.15 A school cannot be held responsible if underprivileged pupils benefit little from the education offered. delete low correlations with other items C6.16 A teacher can make a difference for students from all kinds of home environment. Gender binary C6.17 You cannot expect a school to change the toilet infrastructure for a single transgender student. delete low correlations with other items C6.18 Students sending sexually suggestive photos to each other is beyond the responsibility of the school. delete low correlations with

other items C6.19 Making students aware of inequality between men and women is outdated. delete low correlations with other items C6.20 It is important that we as a school respond quickly and consistently to incidents of sexual harassment among students. delete skewed distribution / ceiling effect C6.21 As a school, it is important to break the traditional divide between subjects that are stereotypically for boys or for girls. LGB C6.22 As a teacher, it is your job to respond to homophobic statements by students. delete suggested by r-square values and factor loading C6.23 It is too cumbersome to adapt all school communication (f.i. the salutation in a letter) to LGB parents. delete low correlations with other items C6.24 It is time that we have attention for LGB sexuality in various parts of the curriculum. delete high partial correlations with C6.25 C6.25 It is our job as a school to support students coming out of the closet during this process. delete low communality score C6.26 As a school, It is normal to support LGB colleagues through thick and thin, even in the event of negative reactions from the school community. delete skewed distribution / ceiling effect A general approach C6.27 It is the responsibility of every teacher to support the language development of pupils delete skewed distribution / ceiling effect C6.28 Teachers have a didactical task in the classroom, not one of raising students or caring for them. delete part of scale with low cronbach’s alpha

C6.29 It is important that your work contributes to the personal growth of students. delete suggested by modification indices and low factor loading C6.30 For a teacher, professional knowledge is more important than knowledge of didactics and psychology. delete part of scale with low cronbach’s alpha C6.31 The future of the current generation of students often concerns me delete low communality score C6.32 I think it is important to mean something personally to students. delete high partial correlations with C6.29 C6.33 A teacher is not a youth or social worker. delete part of scale with low cronbach’s alpha C6.43 A school has the task of combating inequality in society new item added delete suggested by modification indices C6.44 It is every teacher’s job to contribute to a school policy that is mindful of diversity. new item added (Continued) PLOS ONE Measuring teachers’ competences for inclusive education PLOS ONE | https://doi.org/10.1371/journal.pone.0291033 November 8, 2023 9 / 22