Teaching historical thinking in practice: a study of US history teachers’ views on using primary sources in AP and IB history lessons

Analysis of primary sources has been recognised to have a significant impact on the development of students’ historical thinking. This study explored US history teachers’ attitudes and practices to using primary sources by interviewing six history teachers and observing 29 history lessons between August and November 2016 in Indiana and California. The main focus of the study was on the views of International Baccalaureate (IB) Diploma Programme and Advancement Placement (AP) history teachers. Results indicated that all teachers valued the use of primary sources and most of them used sources frequently. Notable was the deficiency of source evaluation in AP and Regular history lessons in those schools which did not offer the IB Programme. The IB teachers mentioned source evaluation as a part of the sourcework throughout, and emphasised the importance of the IB format and other pedagogical support provided by the International Baccalaureate Organization in the use of sources.


Introduction
The detailed examination and evaluation of the primary, original sources and traces of history -diaries, official documents, letters, speeches, photographs, drawings and film -is highly appreciated in the discipline of history and in the pedagogy of historical thinking (Barton, 2005;Charap, 2015;Seixas et al., 2015;Wineburg, 1991aWineburg, , 1991b. Educators and researchers have long called for teaching with primary sources and enquiry methods in history classes (Bain, 2000(Bain, , 2015De La Paz et al., 2014;Wineburg, 2001). Teaching historical skills -sourcing, contextualisation and corroboration -aims to enrich students' understanding of the discipline of history and to encourage history learners to link original sources with the past (Wineburg, 1991a(Wineburg, , 1991b. These skills relate to concepts of historical reading and disciplinary literacy, both of which lay the foundation for understanding historical events and processes through active engagement with historical texts (Nokes, 2010;Wineburg, 1991aWineburg, , 1991b As VanSledright (2014) contends, history domain knowledge can be divided into two main types: substantive knowledge and procedural knowledge. Of these, substantive knowledge can be defined as first-order knowledge about the past and what people typically think of history as a subject: chronological themes, key concepts, stories of history and explanations of the past. Background procedural knowledge relates to organising concepts and ideas, while strategic practices linked to procedural knowledge contribute to learning history by doing history, conducting historical research. With teacher support, students can access procedural second-order concepts such as evidence, accounts, contextualisation, progress/decline, change/continuity, historical significance, human agency and perspectives, and develop their understanding of history as a domain (Lee, 2014;Lightning, 2021). The analysis of primary sources is a way to support students' higher-order thinking skills and engage in the process of historical enquiry, a reasoning process, in which students use research questions, hypotheses, evidence and arguments when conducting their own research about the past. The enquiry method enables students to demonstrate historical thinking heuristics: sourcing, contextualisation and corroboration (Levy et al., 2013). According to Barton and Levstik (2004;Levstik and Barton, 2011), the enquiry approach can be considered social studies' version of the scientific method, which promotes critical thinking skills, advanced literacy (Shanahan and Shanahan, 2008) and active participation in a democratic society.
Meaningful history learning experiences can be created when primary source analysis activities become a consistent part of classroom practice (Dutt-Doner et al., 2007). In terms of the manner in which history is taught, much depends on history teachers' knowledge of their subject (Yeager and Davis, 1996), their understanding of history learning processes and their approaches to the question, 'What is the purpose of history teaching?' (Nokes, 2010). Few history teachers would argue against using primary sources in teaching history (Woyshner, 2010); however, as Boyum (2016) summarises in her work, several inhibitors to the use of primary sources include the US testing culture, time needed to cover a large curriculum and challenges to train students in historical thinking skills. Teaching for historical thinking is complicated and multifaceted, because it requires going beyond chronology and looking at the relationship among series of facts (Spoehr and Spoehr, 1994). Therefore, 'efforts to influence teaching and learning of history should provide opportunities for teachers to develop content knowledge and practices of teaching' (Monte-Sano et al., 2017: 101). In addition, the digital age brings new challenges to the teaching of historical thinking, since, as Stanford University researchers have argued, online internet-based sources should be evaluated by using professional fact-checkers' methods, including opening up multiple windows, scanning the content and laterally checking the validity of the source's claims (Wineburg, 2018). Although there is little research on how the knowledge level of history teachers affects learning processes, current research emphasises the role of the teacher in terms of deepening students' abilities to reason and think historically (Monte-Sano and Cochran, 2009;Nokes, 2010;Wineburg, 2005). In addition, teachers' beliefs about the nature and the teaching of history are interrelated (Voet and De Wever, 2016) and important for understanding teachers' instruction (Yilmaz, 2010).
This study aims to uncover US Advanced Placement (AP) and International Baccalaureate (IB) Diploma Programme (DP) history teachers' views and practices relating to using primary sources and teaching historical thinking in K-12 classrooms (students aged 5 to 18 years). While both curricula emphasise the importance of the analytical use of sources and the teaching of historical skills, this study considers possible differences in these courses' uses of sources, and the reasons behind any differences observed. Uncovering differing source-related approaches and the decisions of teachers teaching different courses may raise awareness of potential challenges and possibilities associated with the use of sources, help future researchers and teacher educators in their work, and promote teaching historical thinking in practice.

Context of the study
The International Baccalaureate Diploma Programme (IBDP) is a secondary education programme for students aged 16 to 19 years, which consists of two academic IBDP years and one preparatory year. The IBDP values critical thinking, enquiry-based learning and academic study skills. IB subjects can be taken at 'Higher' and at 'Standard' level. Historical skills are assessed in each IBDP history final examination paper and, as an integral part of the IB history courses, students are required to write an internally assessed Historical Investigation of 2,200 words, worth 20-25 per cent of their final assessment, using primary and secondary sources. In addition, an Extended Essay (research of 4,000 words) is written on one of the IB subjects, in order to develop students' academic research skills and to engage them in critical thinking. The IBDP history examination consists of three papers, of which Paper 1 (20-25 per cent of the final assessment) is based on the use of primary and secondary sources. Paper 2 (20-30 per cent) and Paper 3 (35 per cent) -only for Higher level (HL) -are essay exams, and none of the history papers include multiple-choice questions. The IBDP teaching philosophy is based on social constructivist theory, and the IB learner profile highlights students' active participation in the learning process (IBO , 2017(IBO , , 2018a. Currently, there are 942 IBDP schools in the US, of which 129 are private schools (IBO , 2018b).
In contrast to IB, the Advanced Placement (AP) history exam includes a multiple-choice question paper in its final assessment. The AP was developed in the US in the 1950s to offer talented students -usually in the last two years of high school -the opportunity to perform more demanding course assignments and to enable students to pursue college-level studies while still in high school (Charap, 2015;Reisman, 2015). The AP history exam consists of a Multiple-Choice Question paper (40 per cent of the final assessment), a Short-Answer Question paper (20 per cent), a Document-Based Question paper (DBQ) (25 per cent) and a Long Essay paper (15 per cent). Of all these, only the Long Essay paper does not require the use of primary sources in students' responses, and the DBQ paper also aims to assess students' abilities to evaluate and synthesise multiple primary sources. On the other hand, the Long Essay paper measures students' skills in using given historical concepts in their responses, and allows them to show their level of understanding by creating synthesis. Like the IB history syllabus, the AP history course curriculum clearly aims to target historical skills, historical thinking and the use of primary sources. On the AP course, historical thinking skills are grouped into four categories: Analyzing Sources and Evidence, Making Historical Connections, Chronological Reasoning, and Creating and Supporting a Historical Argument (College Board, 2017). In addition to the IB and AP curricula, the US National History Standards regarding Regular history courses also aim to stimulate students' critical thinking. Objectives have been set up, and it is expected that teachers should design activities that engage students in using historical thinking (see Common Core State Standards Initiative, 2015;De La Paz et al., 2014;Smith and Breakstone, 2015).
Social constructivist learning theory emphasises learners' own role in creating new knowledge, and collaborative classroom practices are closely connected to the learning process in social constructivism (Baird et al., 2017;Vygotsky, 1978). The sociocultural framework for teaching asks instructors to acknowledge various ways of learning and promotes learning by doing history (Levstik and Barton, 2011). The relationship between assessment, teaching and learning is important, as 'assessment can have a powerful effect on classroom practices' (Wiliam, 2010, as cited in Baird et al., 2017: 321). Theories of learning and assessment should serve the goals of education (Baird et al., 2017). In recent years, history curricula and standard revisers in many countries have emphasised the role of historical thinking and called for changes in assessment. The teaching of historical skills -sourcing, contextualisation and corroboration -has become a subject of regular debate all over the world (Körber and Meyer-Hamme, 2015;Seixas, 2015;Seixas et al., 2015).
Studies on the use of primary sources in history lessons agree that teachers face challenges in bringing the enquiry method, which includes evaluative source work, into their classrooms (Van Hover et al., 2016;Reisman, 2012;Brooks, 2013;Grant, 2003;Hicks et al., 2004;Levstik and Barton, 2011;Nokes, 2010;Wineburg, 1991aWineburg, , 1991b. Teachers' knowledge and understanding of historical enquiry is fundamental for being able to teach it to students (Martin and Monte-Sano, 2008). However, difficulties with organising enquiries and implementing activities (Voet and De Wever, 2016) can sometimes inhibit even knowledgeable teachers in teaching their students about enquiry methods ( Barton and Levstik, 2004).
Given that the inclusion and analysis of the primary sources in history lessons are considered important for historical thinking, this study aims to investigate Advanced Placement and International Baccalaureate Diploma Programme history teachers' approaches to the use of primary sources, and to describe their methods when using primary sources. The research questions explored in this article are:

1.
How do US AP and IB history teachers use primary sources in their classrooms? 2.
What teaching methods do they use when using primary sources?

Data and methods
The objective of this study was to gather information related to US high-school history teachers' methods of using primary sources and their descriptions of their understanding of the relationship between the analysis of primary sources and the teaching of historical thinking. The data consist of interviews with six US high-school history teachers and observations of lessons taught by four of these teachers (N = 29 lessons). The interviews were semi-standardised and open-ended, and they were recorded. The interviews lasted from 25 to 40 minutes and took place before or after lesson observations, which provided additional material to support the interviews. I took notes during the interviews and observations, and, in addition, I collected all the materials provided during the lessons to support analysis. The data were collected between August and November 2016 in the states of Indiana and California. The schools and teachers were randomly selected, and my visits were arranged with the help of the School of Education, University of Indiana and the Fulbright Program. The teachers were informed in advance about the primary source work focus of the interview and observation, and I spent at least a day in each school.
Participation in this research was voluntary and based on informed consent, and all teachers were treated anonymously. Codes correspond to teachers according to schools -for example, the first interviewee in Indiana 1 school was coded as Indiana 1.1.
As shown in Table 1, the teachers had varying levels of experience, and they were teaching courses either with AP exams, mandated by the International Baccalaureate Organization (IBO), or state-mandated, compulsory Regular high-school history courses, which are often assessed with standardised tests. All the schools were public high schools offering compulsory Regular history and optional AP history courses. In addition, the Indiana 2 high school was offering the IB Diploma Programme history courses. Although the AP is represented twice as much as the IB in the sample, only half of those interviewed taught in schools that had no connection to the IB Programme. Some limitations of this study should be noted: a sample of six interviewed teachers is not representative of all US teachers and only one IB history teacher's lessons were observed for the study, so it is not justifiable to draw far-reaching conclusions based on that. However, the work is significant as an exploratory case study which aims to generate insights about the use of primary sources and teaching historical thinking in AP and IB history lessons.
The data were analysed by using qualitative content analysis, 'aimed at providing knowledge and understanding of the phenomenon under study' (see Downe-Wamboldt, 1992: 314). Content analysis as a research method allowed me to use subjective interpretation of the content of text data, and, through a process of coding and identifying patterns and themes, to arrive at comparisons and contrasts, and to determine conceptual explanations of the data (see Hsieh andShannon, 2005: 1278;Miles and Huberman, 1994). I aimed to examine the text for the purpose of classifying large amounts of text into an efficient number of categories that represented similar meanings (see Weber, 1990). After a careful reading and summarising of the data, two categories were formed to describe the differences and similarities in the teachers' use of primary sources. The two categories were characterised as the non-analytical use of primary sources and the analytical use of primary sources. These categories provided a tool to present phenomena at a general level and defined the themes analysed in the study (Hsieh and Shannon, 2005). Additionally, the study utilised ethnographic methods, as data were also collected through observation (Fortune et al., 2013).

Results
In this section, the results of this study are discussed in two categories: the non-analytical use of sources and the analytical use of sources.

Non-analytical use of primary sources
Indiana 1 teachers (AP/Regular) said they use primary sources regularly; however, they also considered the use of sources as 'something extra' and remarked that 'I wish I had more time for the sources' (Indiana 1.2). During a Regular US history lesson a teacher revealed: 'there is a great document about this topic, I wish we could read it, in Government AP lessons they read it' (Indiana 1.1). Answering questions individually, as pairs or in groups, and comparison were mentioned as methods of using primary sources. Based on the observations, both Indiana 1 teachers used quotations from contemporaries as primary sources. For example, quotations from Benjamin Franklin were used as primary sources, and students were asked to: 'Read the quote first individually and think about what it meant to the student him or herself', to 'think about the time period and the meaning of the quote, then apply the quote to something in today's life' (Indiana 1 teachers). For most of the students, it was challenging to understand the quotation's message in contemporary life. Quotations were not analysed and evaluated by their origin, purpose, value or limitations. Reisman (2015) called this situation, when students face challenges to understand differences between their own values and the views of the contemporary historical actors, as the 'historical problem space'. Teachers can help students to engage with historical texts by consistent guidance in analysing the sources, which could include techniques such as the OPVL method (evaluating the origin, purpose, value and limitations of the source) and the HIPPO method (analysing historical context, intended audience, purpose, point of view, and organisation of the source). Both of these methods are tools to teach students how to use sources in an analytical way, and they aim to develop historical thinking skills, contextualisation, sourcing and corroboration (IBO , 2017;College Board, 2017). The Californian AP teacher's view was that he used primary sources a lot: 'It could be ten sources per week, students answer the questions and maybe once a week, one source could be discussed together'. He continued: The AP exam changing to be stimulus-based has made it important to be able to go over more primary sources, but almost on the surface level. It is not that you can dive into a document for twenty minutes or half an hour, you are spending five to two minutes on a document and then we'll move on. (California 1.1) When breaking down the sources, he mentioned using the HIPPO method and a 'same in kind, but different in time' method to give a deeper understanding of 'how much changes happen and how much continuity exists in history'. Individual work was used a lot, students had to become familiar with the source at home or in class, and perhaps answer questions dealing with that source. Class observations also supported this, online sources were available on the teacher's own website, and students spent a lot of time on questionnaires about the content of the sources, with questions such as: 'What does the source say about the Civil War?'; and 'Comparing the two documents above, which side do you think has the easier task ahead of it, and what does the source say about that?' However, no questions concerning the origin, purpose, value or limitations of the source or the HIPPO method were used in source-based activities in these history lessons, neither were there discussions about how to evaluate online sources or mentions of fact-checking (California 1.1).
In the interviews, Indiana 1 and California 1 teachers valued contextualisation, analysis, and comparison and contrast as methods, but those methods were rarely practised in the observed AP or Regular history lessons. Sources were first studied individually, and then sometimes in groups or in pairs; however, interviewees did not consider whole-class discussion a common teaching practice in either school. Observed AP/Regular history lessons in both schools started with a multiple-choice quiz, then continued by going through the topic together with the teacher, individually or as groups, using PowerPoints and potential source work: answering questions, using flash cards for memorising or video clips, and answering questions based on them. It clearly seemed that the use of primary sources in the AP or Regular history lessons were more non-analytical than analytical. Individual learning activities -taking quizzes, copying notes, reading and answering questions -seemed to take up a lot of time in the history lessons, and memorising appeared to be an integral part of history learning throughout the instruction. Primary source material used in the history instruction included speeches, quotations, cartoons, official documents such as government proclamations and the Declaration of Independence and amendments. All of these were used for knowledge sharing, and students were filled with historical facts without evaluation of the sources in question. Teachers acted far more as knowledge givers than knowledge facilitators, and the use of primary sources was a method of providing the students with historical facts (see similar observations in Van Hover et al., 2016; Reisman, 2012).

Analytical use of sources
One of the teachers from the Indiana 2 (IB/AP) school concluded in the interview: 'Any historian would tell you that the most important method of teaching history is through primary sources, there is no better way to understand the people of the time than from their own words, so I utilise primary source documents very frequently' (Indiana 2.1). He mentioned that he uses small extracts of primary sources, but also larger-scale documents such as Machiavelli's The Prince or Voltaire's Candide. In addition to literature, he mentioned using art, music, photography and videos as primary sources. He said: 'I introduce the material, place it. Then we discuss the evaluation of the source, bias and what is omitted, how time affects primary sources and value' (Indiana 2.1). He also highlighted the importance of background knowledge, and the importance of students acquiring that from the textbook or from other secondary sources, and then discussing that context together. 'They should have background knowledge of the person, event or theme first, and then they can read about that by their own words' (Indiana 2.1).
All Indiana 2 teachers mentioned either the HIPPO or the IB format OPVL as methods for analysing the sources. An IB/AP teacher introduced a 'hot seat' method, which is a student-led conversation to prepare students to argue and challenge each other's views with reasoned arguments. Students had to read some source material at home for the next history lesson, and they did not know beforehand who would be leading the conversation on the day of the hot seat placement. The teacher's role was to sit at the back of the class and observe, and perhaps take part if needed. The Indiana 2 teachers made the point that they 'use primary sources frequently, at least once a week'. The AP/Regular teacher stated that: I typically have students to look at the documents. These documents may pertain to a map, a political cartoon or a journal entry. They will then individually identify something that sticks out, how it is used, whether it is a point of view, historical context and what the intended audience would be. After that, the teacher models the use of primary source and the students pair up and look at the central question like the DBQ in AP exam. (Indiana 2.3) The IB/AP teacher concluded: 'I use various kinds of primary sources throughout my teaching, and they read novels of contemporaries to understand a particular historical period' (Indiana 2.2). Analysis of the sources was mentioned in the interviews, and during the IB lesson observation the OPVL method was in use. The IB/AP teachers asked questions such as: 'How would Voltaire's letter about Candide be understood later by historians?'; 'What are the limitations of the source?'; 'What would you need to keep in mind when you read the letter?'; and 'What about the intended audience?' All three Indiana Teaching historical thinking in practice 7 2 teachers (AP, IB and Regular) considered 'the use of primary sources a common practice in teaching history in our school', and, as one teacher noted: In all of our history classes, students are getting a serious evaluation and use of primary sources. One thing we have done in our school, yes we are an IB school, but every student is an IB student in our history classes. IB has forced me to focus on how I look at primary source documents. (Indiana 2.1) Interestingly, the IB/AP teachers mentioned that after becoming familiar with the IB format, they are also using more primary sources and teaching students how to analyse the sources in their AP and Regular history classes.
As described above, the Indiana 2 teachers seemed to have a common understanding of the importance of the analytical use of sources. According to Moje (2008), the teacher's own attitude to the development of historical thinking and understanding emerges as a pathway to advance students' disciplinary literacy. Primary source work can help in this process, if used in an analytical way. Also, Nokes (2010) concludes, drawing on findings from various studies, that without the regular use of primary sources and accurate instruction in historical skills and historical reasoning, students do not develop strategies of historical literacy (Britt and Aglinskas, 2002;Levstik and Barton, 2011;VanSledright, 2002;Young and Leinhardt, 1998). Historians' ways of reading texts contribute to the development of disciplinary literacy and can provide tools for understanding sources more effectively than other curriculum approaches (Wineburg, 2005). Narratives are a starting point in many history lessons; however, disciplinary literacy, thinking, reasoning and writing about history with the help of documents should be developed into historical skills to embrace historical thinking and understanding (Britt et al., 2000).

Discussion and conclusions
The teachers engaged with in this study used primary sources in their history teaching, and most of them mentioned using primary sources on a weekly basis. The interviewees indicated that they understood the importance of analysing the sources and wanted to 'help the students to analyse and understand the context'. However, the analytical use of sources seemed to be a common practice only for Indiana 2 teachers, whether they were IB/AP or AP/Regular history teachers. By contrast, Indiana 1 and California 1 AP/Regular history teachers reported that the evaluation of sources did not always take place in lessons. The AP teachers, who also taught IB history courses, described using instructed primary source work in their history lessons, in which the students were given guidance in the analytical use of sources with the OPVL or the HIPPO method. Furthermore, the pedagogical use of sources had become a common practice in Indiana 2 school's Regular history lessons, since the teachers shared their knowledge and methods of analysing sources. It seemed that Indiana 2 history teachers' collaborative approach promoted peer-coaching to share their expertise (Díaz-Maggioli, 2004) and contributed to a more analytical use of primary sources also in the AP and Regular history classes.
Observations by Brooks (2013), Grant (2003), Nokes (2010) and Van Hover et al. (2016) support my findings that teachers use primary sources and that students work with other students; however, tests are still very common and whole-class discussion quite rare in AP and Regular history lessons. History teachers' own pedagogical knowledge, conceptions of enquiry and historical reasoning influence whether the use of sources is in an analytical manner or not. As Voet and De Wever's (2016) study indicates, history teachers' misconceptions of the enquiry method can lead to misunderstandings of historical reasoning, viewing it as a mechanical assessment of the reliability of sources or as a process of looking up information, both of which contribute to 'shallow historical thinking' (Lightning, 2021: 321). In this case, the deeper historical epistemological challenge of thinking like a historian is replaced by surface-level elements of acting like a historian (Reisman and McGrew, 2018).
In line with previous research, this study highlighted the challenges that AP/Regular history instructors face in their efforts to meet the objectives of the curricula. In comparison with IB/AP teachers, AP/Regular history teachers did not always include source analysis in their lessons, although the teachers valued source evaluation. This difference between what is said in the interview and what is done in the classroom is a common issue concerning interview-based data about teachers' thinking (Chapman, 2017). My findings suggest the possibility that social desirability bias occurred in AP/Regular history teachers' answers to interview questions (Voet and De Wever, 2016). Although AP/Regular history teachers valued foreground and background knowledge, it was challenging for them to rise to the procedural knowledge level in practice. Most of the AP/Regular history teachers used primary sources as knowledge givers, and students were often guided to answer questions without in-depth analysis.
For the IB teachers, this was easier, as they described in the interviews. As the Indiana 2 IB/AP history teacher revealed, 'IB guides the teacher and the students in how to use the skills when analysing sources' (Indiana 2.1). The assessment criteria for IB history obligate teachers to use and teach how to use primary sources in an analytical way, as otherwise it is difficult to succeed in the final examinations. The IBO also requires schools to send teachers regularly to mandatory IB workshops that deal with both pedagogy and historical knowledge. Teachers are also monitored in terms of their grading; every year a sample of students' Internal Assessment work (Historical Investigation of 2,200 words) is sent to IBO examiners for moderation (IBO , 2017).
IB/AP history teachers in this study emphasised the impact of the IB format in their use of sources and, as one teacher compared the programmes from a teacher's perspective: The IB does a really good job of monitoring us, the teachers. We get marks back from IB, and if they don't like how we have graded the Internal Assessment, they change everything. It is very intimidating. It is important for good training. With the AP, nobody really checks if you are doing it. You just meet the syllabus, that is all you do. (Indiana 2.2) As Westhoff (2009) has noticed, even when a teacher understands the discipline and uses primary sources, the lessons do not necessarily include activities related to the teaching of historical skills. This can relate to difficulties in implementation of enquiry activities, lack of knowledge of the enquiry method, the time available for teaching history, prioritising content instead of disciplinary thinking, and contextual influences such as students', parents' and the school's views on teaching history (Voet and De Wever, 2016).
Most AP/Regular history teachers in this study used primary sources, but they did not break down sources with their students or teach the analytical use of sources. Historical skills, sourcing, contextualisation and corroboration were mentioned in the interviews as methods; however, formative tests, quizzes, independent work or surface-level questions took up a lot of class time. As one teacher concluded: The AP is a lot more loose with the questions, there is not so much guidance for the student in the question. I also find DBQ questions, the instructions from the College Board, a little more confusing. Because it does not release the exam answers, it is always a mystery. (Indiana 2.2) As Lightning (2021) concludes, the DBQ questions in AP exams do not require students to resolve contradictions or synthesise, which can lead to surface-level sourcing and corroboration, and they guide not only classroom practices, but also professional development in this direction.
The IB curriculum is based on the constructivist theory of learning, which emphasises collaborative learning and encourages students' active participation in classroom activities. One of the core elements of the IBDP is a mandatory subject, Theory of Knowledge (TOK), which requires students to study how historical knowledge is constructed and what it means to think historically. TOK provides an opportunity to practise historical thinking skills outside the history classroom. Furthermore, IB subject teachers are obliged to collaborate with the TOK teacher by organising skills-specific lessons (IBO , 2018a(IBO , , 2018c. Neither AP nor Regular US history teaching incorporate anything similar into history teaching. Historical skills should be taught, but at the same time AP and Regular US teachers struggle with time management. Moreover, because multiple-choice questions still form a significant part of the assessment of the AP exam, teachers seem to be cautious about excluding tests and multiple-choice questions from their lessons. Although both AP and Regular social studies curricula value evaluative source work and learner-centred pedagogy in history classrooms, the IB/AP teachers seemed to be more familiar with the IB objectives, and especially the implementation of these in classroom practices. While the IB teachers mentioned the support and guidance of the IBO as an important tool in using the sources for pedagogical purposes, the AP/Regular teachers encountered more obstacles to the profound use of sources. The AP programme offers voluntary workshops for teachers, and in response to AP instructors' calls for more assessment guides and scored samples, the College Board has released redesigned online resource materials (College Board, 2017). Further research should study more about the impact of the redesigned AP history course curriculum and the implementation of it. In terms of the curriculum, the Capstone research and seminar is a voluntary course in AP history. However, learning from the IB experience, parts of that could be incorporated into the actual AP history courses to engage students with historians' ways of thinking and enquiring.
History as a subject provides a very rich primary source environment for instruction, and the teacher decides whether interpretative activities, using primary sources, are encouraged in the classroom. US history textbooks have offered very little opportunity to develop those skills, so the significance of guided instruction in document-literacy skills, such as sourcing, corroboration and argumentation, should be acknowledged (Britt et al., 2000). Reading Like a Historian by Wineburg et al. (2011) and Levstik and Barton's Doing History (2011) are examples of high-quality curricular materials which can contribute to the pedagogical use of sources and to the teaching of historical skills (see Van Hover et al., 2016). However, disciplinary instruction requires the implementation of curriculum materials, which alone cannot ensure the teaching of historical thinking in the classroom (Reisman and Fogo, 2016). In addition, Stanford researchers have argued that teaching historical thinking in our digital age requires the skills of a professional fact-checker and the ability to teach these skills to the students, who go online and select sources for their history assignments. The purpose of this teaching is to educate critically reading citizens, qualified to tell the difference between fact and fake (Wineburg, 2018).
This study has highlighted the challenges and significance of the instructed use of sources, while the frequent use of primary sources did not, without tools and support for the teachers, lead to teaching of historical thinking skills. My results suggest that the IBO may be successful in creating a community where teachers emphasise the support provided by IB for their own work. If correct, this finding suggests that tools to work with the sources (TOK-connection, mark schemes, Extended Essay and Internal Assessment work, the nature of the exams) and standards, assessment and professional development resources have a powerful impact on enabling historical thinking to be realised in classrooms. As an IB/AP teacher concluded: 'In the IB, I know what I am doing. I don't know the questions, but I know the format. In the IB you learn the skills and the knowledge' (Indiana 2.3).
My findings are supported by the research literature concerning the AP and Regular history teachers' use of primary sources (Brooks, 2013;Grant, 2003;Nokes, 2010;Reisman, 2012;Van Hover et al., 2016). IB history teachers' attitudes had not been researched before, so this study brings some new insights into the discussion. Future study could compare the AP and IB teachers' obstacles to using primary sources in an analytical way, and how they address those obstacles. In addition, a comparative study on AP and IB students' knowledge and level of historical thinking could help to understand the factors either preventing or promoting historical thinking skills. Furthermore, this study raised the question about what kind of professional development would enable history teachers to meet the demands of the curriculum regarding historical thinking skills. As the Indiana 2 school's experience shows, passing good practices from one teacher to another can be an encouraging starting point and can promote the implementation of instruction in historical thinking skills.