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Secondary Computer Science Teachers’ Pedagogical Needs

The purpose of this study is to identify secondary computer science (CS) teachers’ pedagogical needs in the United States. Participants were selected from secondary teachers who were teaching CS courses or content in a school setting (public, private, or charter) or an after-school program during the time of data collection. This is a qualitative study using CS teachers’ discussions in the Computer Science Teachers Association’s (CSTA) email listserv, responses to open-ended questions in a questionnaire, and discussions in follow-up interviews. Content analysis, thematic analysis and constant comparative method of qualitative data analysis were used to analyze the data. The most common pedagogical need expressed was learning student-centered strategies for teaching CS and guiding students’ understanding with the use of scaffolding and team-management strategies in CS classes. Furthermore, addressing students’ beliefs in CS and their preconceptions in math and reading were important factors influencing teaching CS effectively in secondary schools.


Introduction
Within the United States, more stakeholders have pushed for increased opportunities for computer science (CS) for K-12 students (Code.org Advocacy Coalitian, 2019;Smith, 2016). To meet this need, state departments of education and legislation have implemented numerous policies and resources to broaden K-12 student access to CS (Code.org, 2019). As of 2019, 15 states have made it a requirement that all high schools need to offer at least one computer science class each year (e.g., Indiana, Texas, West Virginia, Arkansas) (Code.org, 2019). Some have even pushed further, requiring all high school students to complete at least one CS course (e.g., Arkansas and West Virginia). However, integrating CS in K-12 schools is a systemic change (Barr & Stephenson, 2011;DeLyser & International Journal of Computer Science Education in Schools, August 2020, Vol. 4, No. 1 ISSN 2513 Wright, 2019) and this change requires well-prepared teachers (Lang et al., 2013). With the push for more CS classes, many states have been trying to identify how to meet this need and improve CS teachers' content, curriculum and pedagogical knowledge through teacher education and professional development programs.
According to the Code.org Advocacy Coalition's State of Computer Science Education (2019) report, the number of teacher certification programs has been increasing in the United States from 27 in 2017, 33 in 2018 to 38 in 2019. Another way this need for more CS teachers has been met is by training teachers from other content areas (e.g., math, science, foreign languages, etc.) through professional development programs (Menekse, 2015). Other programs have created CS teachers through supporting industry. For example, the Technology Education and Literacy in Schools Program supports teachers by partnering industry computer scientists with practicing teachers (DeLyser & Preston, 2015). However, studies have shown that many secondary CS teachers express needing more support beyond the certification programs and professional development programs provided (Giannakos, Doukakis, Pappas, Adamopoulos, & Giannopoulou, 2015;Qian, Hambrusch, Yadav, & Gretter, 2018). This leads to the problem of what CS teachers' challenges and needs are to help them improve their craft of teaching CS.

Teachers' Challenges and Needs in CS Education
In spite of current efforts to offer high quality CS classes in K-12 schools, many teachers have challenges and needs to better teach CS in their classes. These challenges can be categorized as knowledge and skills needs, curricular needs, contextual needs and pedagogical needs (Sadik, 2017). In terms of knowledge and skills, CS teachers share their limited CS content knowledge and skills in various studies (Angeli et al., 2016;Yadav, Gretter, Hambrusch, & Sands, 2016). Yadav et al. (2016) expressed that some CS teachers came from different backgrounds and had to learn CS alone from books and online resources. When these teachers were asked about their knowledge and skills needs, they reported the need for better understanding of programming constructs and more experience on computer programming (Yadav et al., 2016). Furthermore, understanding the principles of coputational thinking emerged as another important knowledge and skills need. CS teachers shared their needs for professional development programs to learn and implement the principles of computational thinking in their CS classes (Fessakis & Prantsoudi, 2019). In terms of curriculum, CS teachers reported needs for more resources for content delivery and assessment (Sentance & Csizmadia, 2016). Most CS teachers reported creating their own curricular resources alone (e.g. books, materials, presentationss) (Brown & Kölling, 2013;Yadav et al., 2016). Finding or creating quality assessment is especially difficult due to problem based and collaborative nature of CS projects (Wilson & Guzdial, 2010). Therefore, teachers expressed the need for assessment materials to guide and grade students' work in CS classes (Vivian et al., 2020). In terms of contextual needs, one of the important barriers was no to limited collaboration opportunities between CS teachers in schools (Tenenberg & Fincher, 2007). Most teachers expressed the feeling of loneliness and asked for a colleague to share ideas and resources (Yadav et al., 2016). Even though there are online communities for CS teachers to collaborate (Sadik, 2017), CS teachers need other CS teacher colleagues to regularly discuss and share ideas and resources in their subject (Cutts, Robertson, Donaldson, & O'Donnell, 2017). Furthermore, CS teachers need more support from their schools in terms of accessing up-to-date computer hardware and software. This show the need for technical support staff who can take care of software and hardware updates and maintanance in schools (Sadik, 2017 (Giannakos et al., 2015;Sentance & Humphreys, 2018;Yadav, et al., 2016). Due to the project and/or problembased nature of CS education courses (Yadav et al., 2016), planning the lessons, keeping the students active and guiding them in their learning process can be difficult (Davenport, 2000). Furthermore, diverse student needs and interests make it more complicated to teach CS in their classes (Schulte & Knobelsdorf, 2007). Therefore, recent studies reported CS teachers' limited experience with student centered practices and teaching students with diverse needs (Che, Kraemer, & Sitaraman, 2019) and suggested conducting more research on CS teachers' pedagogical needs. In order to understand CS teachers' pedagogical needs, an interested reader needs to know what effective teaching and learning means in CS education as well as the successful instructional strategies in CS classrooms.

CS Pedagogy
Teaching is a complex field that requires strong pedagogical knowledge for planning, leading and mentoring dynamic classroom environments and students' learning experience. The International Society for Technology in Education (ISTE) (2011) highlighted that effective teaching and learning in CS education requires knowledge of various instructional strategies and materials. Research on CS education pedagogy has been a topic of interest since early 1980. Four of the successful strategies used in CS education include problem-based learning (Kay et al., 2000;Yadav, Subedi, Lundeberg, & Bunting, 2011), project-based learning (Mills & Treagust, 2003), pair programming (McDowell, Werner, Bullock, & Fernald, 2006), and media computation (Guzdial, 2003). For instance, in problem-based learning (PBL), students work in groups to solve a complex problem using various types of scaffolds (Hmelo-Silver, 2003). In CS education PBL, students are given a complex CS problem in a computer lab environment with tutorials to facilitate their problem-solving process. Project-based learning has also been implemented in CS education. Tasks in project-based learning are designed similar to projects in real life and give learners the opportunity to apply their knowledge in product design and development (Mills & Treagust, 2003). Even though there are similarities with PBL, project-based learning is product focused and requires students to be careful about resources and time, while PBL gives more flexibility in this process. Another important practice, pair programming, is a technique in which two programmers work on the same programming task design and development using one computer simultaneously. This technique was derived from CS industry practices and has been used as an instructional method in both K-12 and higher education. Media computation was a recently developed instructional technique that emphasized learning computing concepts and skills in digital media design (Guzdial, 2003). Guzdial has argued that digital media (e.g. images, videos, audios) can be modified and redesigned using programming and this process can help students learn computation in a more meaningful way. In addition to the instructional methods discussed here, previous studies documented the success of using various other tools and environments in CS education such as computer games (Papastergiou, 2009), virtual learning environments (Esteves, Fonseca, Morgado, & Martins, 2011) and robotics kits (Bers, Ponte, Juelich, Viera, & Schenker, 2002).
Even though CS education research has provided evidence of learning gains with all these strategies, tools and contexts, recent research expressed the need for understanding in-service teachers' explicit challenges in CS pedagogy, especially in student centered learning environments. Due to limited population in earlier levels, this study only targets secondary CS teachers and aims to understand their needs in effective teaching in CS education.
The present study proposes that K-12 teachers may have crucial needs in pedagogy (Hazzan, Lapidot, & Ragonis, 2015;Yadav et al., 2016) and any efforts aiming to prepare CS teachers, initially, need to identify CS teachers' pedagogical needs and answer the following research question: The study aims to reach teachers who are teaching CS content in formal and informal learning environments and explore secondary education teachers' pedagogical needs in teaching CS in the US. It is argued that by identifying needs in this grade range, this study will help: 1. address the specific pedagogical needs of secondary CS teachers, 2. inform administrators and scholars as they develop data-driven professional development programs and resources and inform teacher education programs about in-service secondary CS teachers' pedagogical needs and assist them in preparing courses that address those needs.

Method
Recent literature emphasized the need for improving CS teachers' knowledge and skills in CS pedagogy; however, there is limited exploratory research that explains what that need entails. Using multiple data collection methods for data complementarity and triangulation with rich data (Creswell & Clark, 2017), this study employs general qualitative research design to explore and explain CS teachers' pedagogical needs in detail.

Participants and Setting
Although previous research has recommended beginning CS education as early as kindergarten (Fessakis, Gouli, & Mavroudi, 2013;Kelleher, Pausch, Pausch, & Kiesler, 2007), due to the limited number of CS teachers and courses at the K-5 level at the time of the present study, the researchers focused only on secondary school level.
Participants were selected from secondary teachers who were teaching CS courses or content in a school setting (public, private, or charter) or an after-school program during the time of data collection. In this study, secondary education refers to both middle and high school between grades 6-12. Even though there was a discussion in the literature about the title of the field of study as computing education versus computer science education (Guzdial, 2015), the second was selected because of its broader use in K-12 education and public society. "Model Curriculum for K-12 Computer Science" defined CS as "an academic discipline that encompasses the study of computers and algorithmic processes, including their principles, their hardware and software designs, their applications, and their impact on society" (Tucker, 1996, p. 6). With this description, teachers who mentioned teaching the following and related areas were identified and considered as CS teachers for the purposes of this study: property (Barr & Stephenson, 2011, p. 113).

Data Collection and Analysis
This research was completed in three phases: 3. In the third stage, interviews with eight purposefully selected teachers were conducted to understand CS teachers' pedagogical needs in more detail.

Email Listserv Analysis
In the first phase of the research, due to extensive data in the email listserv, the teachers' communications were analyzed in two steps. In the first step, the researcher used inductive content analysis to identify the conversations related to pedagogy using the teacher communications (3 years, N=1706) in the email listserv (Weber, 1990).
Following the content analysis, in the second step of the analysis in this phase, the email conversations related to pedagogy were analyzed using the thematic analysis technique (Braun & Clarke, 2006) to identify CS teachers' specific pedagogical needs with evidence. Every email identified as pedagogical needs was coded and each of these was categorized into one of seven themes. Table 1 shows examples of codes emerged from the email conversations and depicts how the researchers categorized the codes into the themes. Peer debriefing technique was used in the analysis stage to manage subjectivity, challenge researcher assumptions and discuss alternative interpretations. Initially, one researcher analyzed the email data and other researchers reviewed and provided alternative views to his interpretations. In this phase, the questionnaire was disseminated to CS teacher members of CSTA through their email addresses.

members responded to the open-ended questions with rich comments and examples. The open-ended responses
were included and analyzed using the constant comparative method of qualitative data analysis (Glaser, 1965).
Glaser defines the purpose of the constant comparative method as providing an alternative to analysis, comparing themes and looking for agreements and conflicts ("negative cases or a consideration of alternative hypotheses"), and increasing credibility in the study results. The researcher imported the teachers' responses to Nvivo software and conducted comparison of the email listserv analysis results with the qualitative questionnaire responses. At the end of the questionnaire, the participants were asked to contribute voluntarily in a follow-up, semi-structured interview (3rd phase), in order to elaborate upon their pedagogical needs with examples from their practices.

Interview Data Collection and Analysis
A semi-structured interview protocol was used (Fraenkel, Wallen, & Hyun, 2011)  The interview data collection ended when the researchers decided that the data was saturated, as suggested by Guba and Lincoln (1985): "exhaustion of sources, saturation of categories, emergence of regularities, and overextension." The interviews were fully transcribed. The teacher names and all the identifying information were replaced with pseudonyms. The data was analyzed using the constant-comparative method in the same way as conducted in phase 2 to enhance the findings. This phase also helped the researchers provide more descriptive information about CS teachers' needs with examples from the participants' explanations of their practices.

Issues of Reliability-Validity and Limitations of the Study
The researchers employed various techniques to ensure the standard of trustworthiness of this research (Guba & Lincoln, 1985). In the early stages of the research, multiple researcher meetings were held face to face to establish our research questions, identify our criteria for participant selection and develop and clarify the data collection methods. The data collection process was started using existing teacher discussions in the email listserv. This gave researchers access and opportunity to interpret teacher discussions in a real-life context. This data is triangulated using multiple forms of data sources (questionnaire and interviews) to answer the research question with rich data.
This helped the researchers ensure that the data is credible. This reduced the risk for researcher bias. The interviews in the final phase were fully transcribed and analyzed with multiple researchers' input and agreement. Furthermore, the researchers sent the results to the participants and asked their confirmation of the researchers' interpretations.
This technique is called member checking and have been used in qualitative research to ensure confirmability of the research results (Birt, Scott, Cavers, Campbell, & Walter, 2016). Nevertheless, the study has limitations. Even though all the possible efforts have been made for trustworthiness, the participants were coming from secondary teacher members of one target organization and did not represent all the secondary CS teachers in the US.
Furthermore, there is always risk for researcher bias in qualitative research.

Findings
The pedagogical needs were identified from CS teachers' communications in both the listserv and the questionnaire and expanded on with the interview data. Within the findings, email quotations are marked with "E," questionnaire responses are marked with "Q," and the follow up interviews are marked with "I." Each quotation is also identified with a number indicating a unique participant. For the purposes of this study, teachers' perceived pedagogical needs included the following themes:

Need for Learning Student Centered Strategies for CS Education
Most secondary CS teachers stated that they need to learn new strategies to teach CS content and enhance student learning in their courses. For example, one teacher wanted to know how to teach Linux with new instructional strategies: "I think it's really important for my students to learn Linux but I have no idea how to teach it" (E-2).
Pair programming was one of the student-centered learning strategies primarily discussed in the listserv. For example, one teacher shared her failure in using pair programming in a CS class and asked for advice from other CS teachers: "I have done pairing, but must not have done it correct, because it was not as productive as I'd liked.
What ideas do you have" (E-4)? In the questionnaire, 17 teachers asked for help related to student-centered strategies in CS education. For example, one teacher stressed the need for facilitating students' learning: "I will appreciate further pedagogical help with teaching computer science and facilitating student knowledge, particularly helping students make better connections with the material, and more effectively debug without needing face time or one-on-one time from me" (Q-2). Another teacher emphasized his need for supporting students' learning via scaffolds in a computer-programming course: "I need better strategies for teaching computer programming to students who have never written computer programs before. What's best to teach first, second, etc. I want a scaffolded approach to teaching programming" (Q-3). When asked to explain this need in more detail and provide examples in the interviews, all eight participants described their current practices and explained why they want to learn new instructional strategies. For instance, I-2 described his current practice as "straight lecture"

Need for Strategies Guiding Students Transfer Skills Between Programming Platforms and Languages
In the listserv emails, the participants expressed the need for helping secondary students transfer their skills from visual programming platforms (e.g., block-coding) to text-based environments (e.g., Python), and between textbased environments (e.g., from Python to Java). For example, one teacher emphasized her students' difficulty transferring their CS learning from visual programming environments to text-based programming environments: "In my teaching, it seems that majority of students have difficulty migrating concepts they learned from visual environments into text-based environments. Starting with Scratch/turtle I found that I essentially had to reteach concepts in Python/Java" (E-11). Another teacher shared the same concern between text-based programming languages: "I have found the same thing with students going from python to Java or python to C" (E-12

Need for Strategies Guiding Students' Errors while Coding
The email listserv members stressed the need for strategies addressing students' questions and problems in programming activities in classroom and explained it as the need for analyzing code quickly and guiding the students' CS learning process while coding. One teacher stressed the importance of analyzing code quickly: "When helping students with a project, the teacher needs to quickly analyze what is wrong with the frustrated students' program and then give some advice on how to fix it" (E-14). In another email, one teacher mentioned the need to provide one-to-one guidance to students "We don't provide one-on-one mentoring to students while programming" (E-3). In the questionnaire responses, the participants explained this need as assessing code for correctness, giving students appropriate feedback, guiding students through solving code errors, and creating scaffolding that does not need face-to-face guidance. For instance, one teacher explicitly stated correcting students' code as a need for better CS instruction: "I need help with fixing students code, etc. -sample debugging questions in C++, Java C -and pseudocode" (Q-11). Another teacher emphasized her need for strategies to assess students' code for correctness, structure, and efficiency: "I need to streamline the process of assessing my students' code for correctness, use of comments, ease of use, and grammar and spelling in output statements and comments" (Q10). When asked to explain this need in more detail and provide examples in the interviews, four teachers shared their own strategies and asked for more strategies that can lead their students to finding errors in their code. The interviewees asked for strategies that can lead students to find the errors themselves by exploration. One of these teachers used questioning as scaffolding and asked for more strategies that could guide his students: The easy answer that is the wrong one is to point the student to the bug and say: Well,

Need for Strategies to Facilitate Student Interaction and Collaboration
The email listserv members stressed the need for strategies creating a collaborative classroom environment and guiding student discussions. For instance, when teachers discussed problems in their classroom, several teachers emphasized the importance of creating an environment for learning: "How do kids learn and how do we create an environment to allow that learning to best take place" (E-13). In the questionnaire responses, the participants explained this need as creating a collaborative environment where all the students help each other and attend learning activities: "How to facilitate student independence and helping each other and strategies for when they really are stuck and need individual help and I can't be there for everyone" (Q-12). Another teacher commented about a collaborative environment as a need: "Creating collaborative environment and excitement around problems and solutions" (Q-13). When asked to explain this need in more detail and provide examples in the interviews, four teachers described their own teaching practices, emphasizing the importance of student interaction and broadening the scope of the need to ensure all the students' active participation in collaborative work. One interviewee explained that collaboration is essential in a CS a class:

Need for Strategies Teaching Students with Low Interest in CS
Secondary CS teachers reported that they need more strategies to teach students with low interest in CS, which includes strategies to inform students about the challenges and benefits of CS. Increasing student interest especially became an issue for the participants when a CS class was required or students enrolled in a class when they did not have another option. They believe when a student does know what CS is and understands both the challenges and benefits of CS, their interest and motivation increase. Therefore, some teachers were willing to select students before they were allowed to register. The listserv discussions, questionnaire responses and interviews support these findings. The teachers in the email listserv stressed the need to increase their students' interest and motivation and defined those as preconditions, especially when learning programming. While some teachers discussed that being an elective class reduced the enrollment rates in CS classes, some teachers in the listserv stressed this as a positive factor. One of the teachers described this as: "all it really needs is a desire to learn the stuff, and the fact that it is an elective really helps on that front" (E-12). In the questionnaire responses, 10 teachers commented about student interest in CS classes. In these responses, the teachers stated that increasing interest is a need in the following conditions: • When the course is required, there were students in the class with no to little interest in learning CS (N=5).
• Students came with low interest from various backgrounds (N= 7).
• It was hard to sustain student interest and motivation in programming classes (N=7).
Therefore, those teachers solicited strategies for increasing student interest in CS, as in the following example with underrepresented student populations: Students are now required to take a computer programming class before graduationso I have many underrepresented populations and girls enrolled in my course.

Students who have little interest in the class. I would be greatly beneficial to share strategies on how to motivate students who have little interest in the class. (Q-33)
Sustaining interest in CS classes was also a need mentioned in the questionnaire responses. Most teachers stressed that many students come in with interest in CS, but as the class moves forward to difficult concepts in coding, they lose that interest. They are looking for strategies to sustain interest throughout the course. For instance, one teacher The interviews validated the listserv and questionnaire responses. Seven out of eight interviewees expressed this as a need. When asked to explain this need in more detail and provide examples, the interviewees stated that there were students in their classes who lost interest in the subject and considered it both unrelated to their needs or too challenging. Therefore, most of the interviewees solicited strategies to motivate these students with low interest into learning CS. For instance, one of the teachers stated that there were not many electives for students to choose from in his school and students with low interest were forced to take his class. He expressed the need to be able to help those students to learn CS concepts and skills:

Need for Strategies Teaching Students Who Lack Literacy and Math Skills
For all the participants of this research, math background was reported as an issue for the students in CS classes.
Furthermore, reading comprehension tended to be a problem in some contexts where there were economically disadvantaged and minority students with limited content knowledge in general. Secondary CS teachers stated that they need more strategies to teach students with low mathematics and reading comprehension skills. The email listserv participants stated that some of their students lacked fundamental skills, which influenced their understanding and ability to apply the concepts and skills in CS classes. One teacher described the problem: "Somehow some of my students have core (base) knowledge missing or so confused that it makes it hard for them to progress" (E-37). Math, especially algebra, emerged as the most important skill that students needed to be successful in CS classes: "I have many instances in which I have to divert my curriculum to teach them Algebra concepts that should have known" (E-39). Reading comprehension was another factor identified in the listserv, especially for understanding instructions in CS classes. One teacher highlighted her concern: "Reading comprehension is a struggle. Some of them can't follow specific instructions and don't understand the importance of flawless execution, error free and clear thinking when writing programs" (E-39). In the questionnaire responses, 25 teachers shared opinions about fundamental skills they consider important for learning CS and their need for strategies in dealing with those students who lack them. For instance, one teacher emphasized this as an evolving need with CS becoming more available in schools:

Discussion
The overall findings suggest that secondary CS teachers need community help from other teachers to meet their needs in teaching CS (Ni & Guzdial, 2012). This study focused on the pedagogical needs and found the participants' primary need as learning and using student-centered learning strategies in CS classes. Specifically, secondary CS teachers stressed the need for scaffolding strategies that can guide students in solving computing problems in various levels at the individual level and in teams. The sections below discuss the participants' pedagogical needs in detail.

Learning and Applying Scaffolding Strategies in CS Classes
The primary discussion was evolved from the need for student-centered learning strategies in solving CS problems in coding activities. In order to be successful in learning CS, students need guidance while solving problem based activities (Hmelo-Silver, 2004;Mayer, 2003). This guidance is conceptualized as scaffolding in the literature.
Scaffolding helps students to complete complex learning tasks that are difficult to achieve without assistance (Belland, 2014;Wood, Bruner, & Ross, 1976). Scaffolding makes the learning process more manageable  (Hmelo-Silver & Bromme, 2007) and is of primary importance in supporting students to reflect on their own learning and develop higher order thinking skills (Azevedo, Cromley, Winters, Moos, & Greene, 2005;. Brush and Saye (2002) defined two types of scaffolding: hard and soft. Hard scaffolds are planned in advance such as multimedia resources (e.g. helpful websites). Soft scaffolds are more dynamic and happen simultaneously. Examples of soft scaffolding include teachers' using questioning strategy to guide their problemsolving processes. Guzdial (2015) also stressed scaffolding as one of those primary conditions for effective CS education. In the present study, secondary CS teachers identified similar issues. In CS, when students are assigned a problem, they often use trial-and-error when they are not given adequate facilitation (Shute, Sun, & Asbell-Clarke, 2017). Trialand-error is not an efficient problem-solving strategy (Sengupta, Kinnebrew, Basu, Biswas, & Clark, 2013), it takes time and often yields no results. The findings suggest a more purposeful design of computational problem solving (Shute et al., 2017), with teachers' scaffolding embedded in the process and facilitating students' coding practices. Secondary CS teachers want to learn more strategies to answer students' questions during coding practices, particularly when students are debugging their own codes, finding and fixing errors, and increasing the efficiency of their code. These are important components of computational thinking in programming activities (Grover & Pea, 2013). Students tend to expect teachers to point out their mistakes, but this is not an effective teaching method. Providing feedback in the form of guiding questions helps students to assess and reflect on their own learning (Nicol & Macfarlane-Dick, 2006).

Creating a Collaborative Teamwork Environment in CS Classes
The results suggest that teachers need tools and strategies to make sure all students actively participate and equally contribute during teamwork and recommend further research to identify successful team building and management strategies, especially in pair programming activities. Teamwork is a crucial part of CS learning and benefits students' learning experience through sharing information and receiving feedback within a social community of peers (Sancho-Thomas, Fuentes-Fernández, & Fernández-Manjón, 2009). In pair programming, students work collaboratively in teams. Pair programming involves strong pair collaboration within teams, with less teacher involvement (Nagappan et al., 2003). It is not surprising that teachers who requested feedback in the email listserv about pair programming were also looking for team building and management skills to create successful collaborative environments. The findings suggest that CS teachers want to make sure that all their students actively participate in teamwork. Poor teams often involve one expert student taking all the responsibility, while other members become passive participants who may not benefit from the learning opportunities (Shimazoe & Aldrich, 2010). Cooperative team work is the primary condition of successful pair programming practices in computer programming courses (Umapathy & Ritzhaupt, 2017). Teachers in the study also solicited strategies for creating a collaborative learning environment where students search for answers from their partners rather than the teacher.
It is important to note that CS teachers have limited time during a class period to answer all the questions, and team work becomes an important opportunity to alleviate those problems (Sancho-Thomas et al., 2009).
However, teachers need to be aware of the differences between team members in terms of knowledge/skills and personality (Ally, Darroch, & Toleman, 2005).

Transferring Knowledge and Skills between Programming Languages and Platforms
Even though limited examples were found, the findings suggest that secondary teachers need strategies to help ISSN 2513-8359 14 students transfer learning and build on their previous knowledge in subsequent CS classes. Transfer of learning is important, not only to make connections between concepts and skills, but also when developing new learning (Driscoll, 1994). Transfer of learning can make CS experiences more connected and meaningful. This need was emphasized in previous CS education studies related to programming. For example, learning the concepts and logic of programming (e.g., variables, loops) from visual programming tools (e.g., Scratch) in middle school helped students learn complex programming concepts more easily in text based languages, and also increased enrollment numbers in CS classes (Armoni, Meerbaum-Salant, & Ben-Ari, 2015). In another study, Franklin et al.
(2016) conducted a study with high-school students' and reported this as a challenge. Franklin et al. reported this as an important concern and recommended the teachers help students see the connection between visual programming and text-based programming activities in their instruction.

Increasing Students' Interest in Learning CS
Most secondary teachers in this study reported that students in their classes do not perceive a connection between CS and their personal lives or their professional futures; thus, they do not value learning CS. Therefore, if teachers want to increase students' positive beliefs and interest in learning CS, they need to find ways to make CS relevant to their students' lives (Tew, Fowler, & Guzdial, 2005). For example, Umbleja (2016)  1. Introducing CS to students early in their education through short-term programs and local campaigns, 2. Developing curriculum that represents diverse student interests, 3. Defining short-term benefits and learning outcomes Short-term programs and national promotions (e.g., code.org) have been reported as helpful in gaining interest in CS (Wilson, 2014); however, sustaining that interest in the classroom may be challenging. The findings suggest that teachers need to constantly define goals and benefits for students to retain their interest. Therefore, a placebased education approach may be a successful strategy to define goals for students to serve their local communities through service learning projects. Service learning projects in CS higher education provide long-term motivational benefits for learning (Sanderson, 2003) while creating an engaging and motivating learning environment in K-12 (Billig, 2000). However, K-12 CS education literature appears to be limited in this regard. Service learning approaches may be promoted and further research should explore effective strategies to employ service learning in K-12 CS education.

Teaching Students with Limited Math and Reading Background
The findings suggest that low abilities in Math and reading create challenging teaching environments for CS teachers trying to manage and teach students with widely varying needs and learning goals. For example, CS teachers reported that some students were unable to do simple calculations and read instructions to complete simple programming tasks. These findings align with previous research regarding the importance of math background in International Journal of Computer Science Education in Schools, , Vol. 4, No. 1 ISSN 2513 learning CS. In a study with 123 first-year introductory programming courses at a higher education institutions, Bergin and Reilly (2005) found that mathematics ability is one of the important predictors of students' success in programming classes. Grover, Pea, and Cooper (2016) reported correlation between middle school students' prior reading and Math abilities, and learning computer programming. Regarding students' math and reading comprehension, secondary CS teachers were looking for strategies to guide students with problems in those areas before they register for CS classes. However, this goes against the national goal known as "CS for All" (Smith), and would create bigger problems in the future. In fact, several teachers in the study mentioned that "CS for All" may create classes that are difficult to manage. Teachers need strategies to help them deal with wide range of skills in math and reading among their students. Further research may be helpful to develop student-centered practices for teaching students with different math and reading skills in secondary CS classes.

Conclusion
In the present study, the data in the email listserv demonstrated a wide range of teachers' self-reported needs in a natural community setting. Furthermore, rich discussions evolving from the listserv discussions allowed the researchers to enrich the findings with the questionnaire and interview data. Similar studies were also conducted to understand CS teachers' needs in smaller samples. This study is important to validate the findings of previous studies and start new discussions in the area with rich data. Similar to this study, previous studies recommended using student-centered strategies for effective CS education (Hazzan et al., 2015). For example, current literature discussed problem-based learning (Mills & Treagust, 2003) and pair programming (McDowell et al., 2006).
Furthermore, scaffolding and facilitating students' learning in student centered environments were discussed in the CS education literature (e.g. (Caspersen & Bennedsen, 2007). However, this study provided evidence that secondary CS teachers try to use pair programming, problem-based learning and scaffolding in their classes but they were not satisfied with the outcomes of their efforts. Secondary teachers need feedback to improve their practices.
Although this study represents a large population of secondary CS teachers, the participants in this study are U.S. members of one international organization and do not represent all the CS teachers in the U.S. Furthermore, the findings are not suggested to be generalized. The data represents teachers who are members of the CSTA and were identified as secondary CS teachers in the email listserv based on available information. Although all the efforts have been made to exclude them, there is a small risk that some elementary teachers or higher education faculty might be included in the findings. This study suggests that future studies need to be conducted to explore the following topics in CS classrooms: • Successful student-centered learning strategies (e.g. PBL and pair-programming) in secondary CS classes • The development of strategies to increase student interest and motivation in learning CS.
Furthermore, it would be helpful to develop research studies that observe successful teachers' practices in their classrooms. Action research studies that allow teachers and researchers to work together (Lang et al., 2013) and aim to address secondary CS teachers' needs in practice would create helpful information for practicing teachers.
Developing PD programs based on the suggestions of this study may promote and develop data-driven PD programs for teachers. With the goal of CS for All, this study may be replicated to explore the needs of elementary CS teachers.

Disclosure statement
No potential conflict of interest was reported by the authors.