One of the problems concerns the participants of the large-scale questionnaire study. As it was mentioned above, one of the main issues with using online questionnaires is the fact that their completion is not obligatory for the participants, so even if the researcher goes to great lengths to reach as many potential participants as possible, a respondent can simply not click on the link (choose not to participate) or choose to opt out whenever they want to during completion.

The risk of participant self-selection was even higher because of the controversial nature of the research topic in question. What I learnt from the pilot study I conducted on teachers’ attitudes towards dealing with controversial issues (Divéki, 2018) is that it can be assumed that mostly teachers who feel strongly about the importance of dealing with such issues take the trouble to fill in a 20-minute-long questionnaire. There are two ways I intended to deal with these issues. First, I gave the questionnaire a catchy but not too revealing title to attract more teachers to fill it in without prejudices about the investigated topic. Secondly, I was going to approach ELT teacher team leaders and ask them to get their team to fill in the questionnaire at the beginning of a meeting. In this way, I hoped to even out the number of enthusiastic and less enthusiastic participants. However, this endeavour turned out to be more challenging as many schools in the country do not tend to display team leader functions on their websites, or if so, they do not always provide their contacts. So as to involve participants from as many teaching contexts as possible, I collected English teachers’ email addresses from school websites and sent them the link to the questionnaire directly. I even offered an incentive for them: the link to the collection of activities designed for the classroom study was included at the end of the questionnaire, which, based on the statistics on my website, many respondents opened.

The second limitation concerns the classroom study. As it was mentioned above, owing to the pandemic, this phase of the research became quite problematic; first, owing to emergency remote teaching and then, owing to the limited time frame and the approaching second lockdown. Because based on Hopkins’ (2008) recommendations, I wanted the study not to be “too demanding of teachers’ time” (p. 59), and in such a situation I did not want this project to be an imposition, I decided not to include classroom observations in the design. Based on my personal experience and personal communications with the participants, they were struggling to keep up in this period, and apart from the apparent demands of the pandemic on their lives and their mental health, they had to develop their techno-pedagogical skills in a relatively short amount of time to be able to successfully teach their students online (Fekete & Divéki, 2022). I opted for not observing lessons where many students were, according to their teachers, sitting with their cameras turned off, not ready to participate. Moreover, in the secondary school pilot, some teachers said that they did the worksheets with their students in an asynchronous manner, which would have been unobservable. In the main study, the fact that some classes had to be quarantined if there was a person who tested positive would have complicated the observations. Also, to do the observations correctly, and avoid the observer paradox (Mackey & Gass, 2012), I should have also observed the classes before they did the activities. Finally, even when in-person teaching was possible in schools in the Autumn semester, everyone was wearing masks, only the teachers and their students could go to the schools and having guests was strongly discouraged. Even though this issue made triangulation more difficult, I aimed at checking the progress of the groups by keeping in touch with the participating teachers regularly and involving multiple instruments to gather data.

The third limitation concerns the focus of the studies. The OECD’s main aim with creating the global competence framework was to measure students’ global knowledge, skills, attitudes, and values; nevertheless, the studies only focus on developing students’ global competence and not on assessment. Moreover, all four dimensions of global competence did not appear markedly in the investigations as the studies were mostly concerned with developing students’ knowledge, skills, and attitudes and not so much their values. The reason for the apparent avoidance of values from the interview questions and questionnaire items is that values education is still regarded as a complex and controversial topic in educational sciences: values are difficult to define, contextualize and assess, it is questionable what values one should teach, and it is even more questionable whether teachers have the right to impose their own values on students (Read, 2018). Nevertheless, as Freire (1985) and Giroux (1997) posit, it is impossible to be values-free when teaching, as teachers convey values with their behaviour in the classroom and the way they communicate with their students (Read, 2018). With this controversy in mind, I decided not to ask questions about values; however, values did come up in teachers’ answers quite often, so they are reported in Chapters 4 and 5. Another issue with the focus of my investigations is that RQ2 and its sub-questions only enquired into the ways tutors and secondary school teachers develop the knowledge dimension in their students. The reason for selecting the knowledge component as my primary focus was not that it is the most important element of the global competence framework, but some empirical studies (Haynes, 2009; Yoshihara, 2013) led me to believe that teachers tend to avoid controversial content and many global, local, and intercultural issues may be regarded as controversial. With this tendency in mind, it seemed logical to investigate how teachers incorporate controversial issues into the curriculum for GCD. Therefore, this research problem prompted me to only focus on the knowledge dimension in Studies 1–4 and on the knowledge, skills, and attitudes dimensions in practice in Studies 5–8.