... Self-efficacy has a positive effect on other areas of teaching: stress reduction in the case of challenging behaviour of students with ASD (Leblanc, Richardson, & Burns, 2009;Lepper, & Probst, 2005), and reduction of the risk of professional burnout (Boujut, Dean, Grouselle, & Cappe, 2016;Boujut et al., 2017;Corona, Christodulu, & Rinaldi, 2016;Jennett, Harris, & Mesibov, 2003;Ruble, User, & McGrew, 2011). A sense of self-efficacy affects the formulation of appropriate expectations for students regardless of the type of school (special vs mainstream) (Rubie-Davies, 2007); it also improves the quality of work with students with ASD by increasing the effectiveness of appropriate educational strategies (McGregor, & Campbell, 2001;Park, & Chitiyo, 2011;Sanini, & Bosa, 2015), and it increases the likelihood of students with ASD experiencing educational success through effective inclusion (Jennett, Harris, & Mesibov, 2003;Busby et al., 2012;Rodriguez, Saladan, & Moreno, 2012;Park, Chitiyo, & Choi, 2010;Sanini, & Bosa, 2015). The use of a non-standardised tool to measure teachers' confidence in their competencies (self-efficacy) resulted from the nature of the ASD-EAST project and the need to carry out intercultural comparisons, which otherwise would not have been possible due to the lack of adaptation of standardised tools in the countries being compared. ...