Is It Reliable for Physical Education Teacher to be A Head teacher? A Mixed-Method Study* Ping Bai, 1 Jiacheng Zhang, 1 Jijun Yao 2 1. Lianyungang Huajie Experimental School, Lianyungang 222000, China. 2. Nanjing Normal University, Nanjing 210024, China Abstract. To discuss physical education (P.E.) teachers serving as head teachers, it should be reasonable and evidence-based. Previous studies did not provide sufficient scientific evidence to answer this hotly debated question. Therefore, this study first adopted rigorous experimental re- search methods, focusing on analyzing whether a P.E. teacher serving as a head teacher would affect student performance. On this basis, the ro- bustness of the experimental results was verified through qualitative re- search. The results showed that a P.E. teacher serving as a head teacher would not adversely affect students’ academic performance and maybe more conducive to students’ overall development. Based on this conclu- sion, we further suggested how to improve the appointment and man- agement of head teachers. Best Evidence in Chinese Education 2021; 7(2):949-960. Doi: 10.15354/bece.21.or019. How to Cite: Bai, P., Zhang, J., & Yao, J. (2021). Is it reliable for physical educa- tion teacher to be a head teacher? A mixed-method study. Best Evidence in Chinese Education, 7(1):949-960. Keywords: Physical Education Teacher, Academic Performance, Experimental Research About the Authors: Ping Bai, Director-General, Lianyungang Huajie Experimental School, Lianyungang 222000, China. Email: 2691285308@qq.com. Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No.2, 2021 950 About the Authors: Jiacheng Zhang, Principal, Lianyungang Huajie Experimental School, Lianyungang 222000, China. Email: 1983167366@qq.com. Correspondence to: Jijun Yao, Professor, School of Educational Science, Nanjing Normal University, No. 122, Ninghai Rd., Nanjing 210024, China. Email: yaojijun_njnu@163.com. Funding: This study was one of the accomplishments of Nanjing Normal University’s horizontal project “Quality School Construction Based on Evidence-Based Education Research” (Sponsor: Jiangsu Huajie Education Group). Meanwhile, this study was also funded by the “Jiangsu University Advantage Discipline Construction Project Funding Project” (PAPD). Conflict of Interests: None. *: A head teacher, aka Ban Zhu Ren in Chinese, is a teacher who is fully responsible for the learning, health, and life of the students of a class in a school. She/He is the organizer, leader and educator of a class, as well as the coordinator of teaching and education work of all the teachers in a class. © 2021 Insights Publisher. All rights reserved. Creative Commons Non Commercial CC BY-NC: This article is distributed under the terms of the Crea- tive Commons Attribution-NonCommercial 4.0 License (http://www.creativecommons.org/licenses/by- nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed by the Insights Publisher. Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 951 Question HETHER a physical education (P.E.) teacher can serve as a head teacher is not a new question. On the one hand, “non-core subject” teachers, including P.E. teachers, have long been used as head teachers; on the other hand, there has never been any policy or regulation in China that prohibits P.E. teachers from serv- ing as head teachers. However, in reality, “non-core subject teachers,” including P.E. teachers as head teachers, have indeed become a “problem.” In recent years, the topic of P.E. teacher serving as head teacher has become a hot topic of public attention. Students tend to “despise” non-core subjects psychologically, regard non-core subject classes as relaxing time; their teachings of non-core subject teachers are also ignored. It creates numerous obstacles to the class management of non-core subject teachers (Shi, 2021). What is more, parents complained to the local administrative department because the school arranged a P.E. teacher as the head teacher and worried that this would affect the student’s academic performance. Although the government and schools do not support such complaints, the incident itself reflects parents’ anxiety about class management under the fierce academic competition (Zhao, 2020). In this case, merely dismissing the complaint or giving a general explanation is often challenging to eliminate the parents’ doubts; simplistically accusing the parents of “unreasonable” is even more detrimental to the problem’s solution. When dealing with such problems, administrators should not only be rational but also have evidence. If we can come up with more evidence of the effectiveness of P.E. teachers as head teachers, regardless of whether this evidence is in line with our expectations, it will make our decision-making and management based on science, which can dispel doubts and improve class management. So far, researchers have analyzed the phenomenon of P.E. teachers serving as head teachers. This kind of authors are mostly front-line managers and teachers, and related researches were basically theoretical discussions and experience summaries. In terms of research content and conclusions, most of them discussed the advantages, strategies, and significance of P.E. teachers as head teachers. They thought that the P.E. teacher’s role as a head teacher was a breakthrough P.E. teacher’s spiritual character, life attitude, and sports emotions make the obvious superiority for P.E. teacher to be a head teacher (Qi & Wang, 2020). Some studies also explored from the perspective of moral education and the cultivation of students’ core literacy. It is believed that P.E. teacher as a head teacher helps to shape students’ positive, tenacious and unyielding mental outlook with rich sports emotions, and then cultivate students’ good moral quali- ties, thereby promoting students’ all-round development (Gong & Zeng, 2020). At the same time, some studies have discussed the shortcomings of P.E. teacher as a head teacher. For example, because the P.E. teachers have fewer class hours, she/he often does not have enough grasp of the classroom situation, and it is difficult to have more in-depth contact and understanding of students. P.E. teachers’ knowledge has limita- tions, which is not conducive to helping students improve their academic performance. The relatively “weak” status of P.E. teachers is not conducive to coordinating the rela- W Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 952 tionship with other teachers in the classroom, thereby affecting the authority of class management (Chen, 2014). What needs to be pointed out is that despite the constant discussion about who the head teacher is, in reality, there is a need to evaluate the effectiveness of P.E. teach- er as the head teacher. Nevertheless, so far, there are few rigorous empirical studies on this issue in existing studies. Relevant discussions are mostly experience summaries or value discussions. The lack of rigorous scientific evidence makes it difficult for both researchers and managers to respond effectively to this problem in the class manage- ment process. In response to this, this research will analyze the effect of P.E. teacher as a head teacher through an experimental study, supplemented by qualitative research evidence, especially its impact on students’ academic performance. While responding to public concerns provide a scientific basis for optimizing head teachers’ staffing and improving class management. Experimental Methods Ideas Although in reality, the influence of head teachers on students is manifold. However, considering that the current public opinion is mainly concerned with the impact of P.E. teacher as a head teacher on student performance, the dependent variable investigated in this study was student academic performance. The core question to be answered was: Will a P.E. teacher acting as a head teacher hurts students’ academic performance as some parents worry about? To this end, our primary research idea was to analyze the impact of PE teacher as a head teacher by comparing the academic performance of PE teacher as a head teacher class and non-PE teacher as a head teacher class under the control of related confounding variables. In this study, since many factors affect student performance, the head teacher candidate is the only one-factor affecting student performance. If the relevant influenc- ing factors are not controlled, the results obtained are not reliable how to eliminate the influence of confounding variables and get more robust conclusions that can reveal causal (rather than related) relationships have always been complicated in social science research. However, experimental research is often a common way to solve this problem. The current leader in evidence-based education research, Professor Robert Slavin of Johns Hopkins University in the United States, believes that well-designed experimental research can control confounding variables and reveal causality. Therefore, it is very suitable for the value judgment of different educational interventions (Slavin, 2020). The basic principle is to construct an experimental group and a control group with small differences in confounding variables and the intervention variables to evaluate the in- tervention’s effect. Because of the samples constructed in this way, there is no signifi- cant difference in the confounding variables between the experimental and control groups. If, after the end of the experiment, there is a significant difference between the two groups of experimental results, it can be judged that the intervention variable is most likely to be the cause of the difference (Angrist & Pischke, 2009). Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 953 Based on this idea, in the research process, we regard different head teacher candidates as the basis for grouping. The class with P.E. teacher as head teacher is re- garded as the experimental group; the class with the non-P.E. teacher as head teacher is regarded as the control group. In the case of well-controlled confounding variables, the influence of P.E. teacher as a head teacher on students’ academic performance was in- vestigated by analyzing the difference in academic performance between the two during the experiment period. Subjects This research object is the middle school department of Lianyungang Huajie Experi- mental School Affiliated with Nanjing Normal University. The school is a nine-year consistent private school, of which the middle school has 54 classes and 11 P.E. teach- ers. The average age of school teachers is about 27 years old, and most teachers have a teaching experience of 4-5 years. The reason for choosing a middle school is that mid- dle school students in China face more significant pressure to enter high school than elementary school students. In this case, schools and parents will be more cautious when facing P.E. teachers as head teachers. Previous studies have also shown that be- cause middle school students are in a rapid physical and mental development stage, teachers’ management styles often significantly impact students (Wang et al., 2009). Since the school is a boarding school, head teachers’ workload is relatively large, and most are female teachers. There are often teachers who are unable to under- take class management due to personal or family reasons. In response to this situation, the school has reformed head teacher selection many years ago, boldly enabling P.E. teachers to take up the work of head teachers. At present, except for two female P.E. teachers who are not head teachers due to pregnancy; all other P.E. teachers are head teachers. In the three grades of the middle school, including the graduating class, P.E. teachers serve as head teachers, which provide a good research foundation for this study. Study Procedures A well-designed experimental study has stricter standards, including control of pre-test differences and confounding variables, sufficient sample size, and a long experimental period (Cheung & Slavin, 2016). Based on the above research ideas, we will use one academic year to carry out experiments from September 2019 to June 2020. To control the differences between groups, the school randomly sorted students and teachers into classes based on the seventh-grade placement test results and the final results of the eighth and ninth grades of the previous academic year. It aimed to ensure no significant differences in each class’s pre-test scores, the teacher’s teaching experience, ability, and the students’ family background. During the experiment, we collected five results, including the results of the placement test, the midterm, and the final results of the two semesters. Simultaneously, through interviews, field observations, text and video analysis, and other qualitative Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 954 research methods, the head teacher’s work materials are obtained to more robustly veri- fy the experimental results and describe their work more comprehensively. Results In June 2020, after an academic year of experiments, we obtained the final experimental results. To eliminate the influence of the test paper’s difficulty and the distribution of data, we processed the original score of the test and converted it into a percentile. The advantage is that the academic progress or regression of students can be evaluated ac- cording to the changes in their percentile grades, so as to eliminate the influence men- tioned above caused by different testing tools (Kolen & Brennan, 2014). Table 1 shows that at the beginning of the experiment, the performance gap be- tween the experimental group and the control group in each grade was tiny, and all in- dependent sample T-tests were not significant. To measure the difference between the experimental and control groups more accurately, we also calculated the effect size of the difference between the groups based on the results of the independent sample T-test. The reason for estimating the effect size was that the traditional null hypothesis test results were often greatly affected by the sample size, and the effect of independent var- iables could not be measured. Cohen believed that people often only paid attention to whether the results were “significant.” It seems that as long as the p-value was less than 0.05, the study results were valuable. This confused the difference between significance and practical effect. Even if the experimental result was significant, it did not mean that the independent variable’s effect was sufficiently “large” (Cohen, 1992). Therefore, the calculation of effect size was first introduced in psychology, and different types of ef- fect sizes were used to express the size of experimental effects. In this study, Cohen’s d value was used as the effect size to measure each stage’s practical effect. The specific calculation method is: (1) Among them, and are the mean values of the experimental and control groups, respectively, and is the pooled variance. The larger the value of d, the more significant the difference between groups caused by the independent variable. Cohen once suggested using 0.2, 0.5, and 0.8 as critical points to distinguish small, me- dium, and large effect sizes and combine previous research and actual conditions to interpret the observed effects (Zheng et al., 2011). Based on this, we calculated the re- sults of the independent sample T-test of each test and calculated the effect size. The specific calculation results are shown in Table 1. Table 1 shows that the difference between each grade group’s effect size is minimal at the pre-test. This means that we have the reasonable control of the pre-test differences. After randomization, there was no significant difference between the exper- imental group and the control group. The difference between the experimental and con- trol groups was mainly due to the head teacher’s different subjects. If there was (or no) Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 955 Table 1. Experimental Results of the Influence of Physical Education Teachers as Head Teachers on Student Performance. 7th Grade 8yh Grade 9th Grade Placement Test Placement Test Placement Test No. Avg SD T ES No. Avg SD T ES No. Avg SD T ES Exp 202 0.50 0.29 0.07 0.01 125.00 0.50 0.30 -0.13 -0.01 201.00 0.50 0.29 0.05 0.00 Ctrl 805 0.50 0.29 711.00 0.50 0.29 613.00 0.50 0.29 2019-2020 School Year First Semester 2019-2020 School Year First Semester 2019-2020 School Year First Semester No. Avg SD T ES No. Avg SD T ES No. Avg SD T ES Exp 199 0.53 0.29 1.67 0.13 131.00 0.46 0.29 -1.84 -0.17 206.00 0.52 0.29 1.19 0.10 Ctrl 861 0.50 0.29 723.00 0.51 0.29 616.00 0.50 0.29 2019-2020 School Year End of the First Semester 2019-2020 School Year End of the First Semester 2019-2020 School Year End of the First Semester No. Avg SD T ES No. Avg SD T ES No. Avg SD T ES Exp 197 0.53 0.30 1.70 0.13 129.00 0.48 0.31 -0.92 -0.09 206.00 0.52 0.29 1.29 0.10 Ctrl 854 0.49 0.29 719.00 0.51 0.29 614.00 0.49 0.29 2019-2020 School Year Second Semester 2019-2020 School Year Second Semester 2019-2020 School Year Second Semester No. Avg SD T ES No. Avg SD T ES No. Avg SD T ES Exp 195 0.51 0.30 0.53 0.04 124.00 0.46 0.28 -1.74 -0.17 204.00 0.52 0.29 1.10 0.09 Ctrl 836 0.50 0.29 708.00 0.51 0.29 608.00 0.50 0.29 2019-2020 School Year End of the Second Semester 2019-2020 School Year End of the Second Semester 2019-2020 School Year End of the Second Semester No. Avg SD T ES No. Avg SD T ES No. Avg SD T ES Exp 196 0.51 0.30 0.44 0.03 126.00 0.46 0.30 -1.58 -0.15 202.00 0.51 0.29 0.72 0.06 Ctrl 838 0.50 0.29 708.00 0.51 0.29 595.00 0.49 0.29 Note: The T value in the above table results from the independent sample T-test of the experimental group and the control group. The p values corresponding to all T values are more significant than 0.05, which is concise. No p-value is reported in the table. Exp: Experiment; Ctrl: Control; Avg: Average; SD: Standard Deviation; ES: Effect Size; T: T Value. significant (or insignificant) difference in performance between the experimental and control groups during the experiment or at the end of the experiment, we could judge that the difference in selecting head teacher caused this change. The results in Table 1 show that the difference between the experimental group and the control group’s previous examination results is not apparent in the entire exper- iment process. Among them, when the seventh grade was divided into classes, the ex- perimental group had a fragile performance advantage compared to the control group; the ninth grade experimental group and the control group had almost the same perfor- mance, and the effect sizes of the two grades were 0.01 and 0, respectively. By the end of the study in June 2020, the independent sample T-test results of the two grades were still not significant, and the effect sizes had become 0.03 and 0.06, respectively, indicat- ing that the experimental group where the P.E. teacher served as head teacher had fur- ther expanded its performance advantage compared with the control group, but the ex- pansion of such advantages were fragile and did not show statistical significance. In the Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 956 pre-test of the eighth grade, the experimental group had an extremely weak disad- vantage compared with the control group, and the difference was also not significant (T = -0.13, p > 0.05). At the end of the study, the effect size of the eighth grade changed from -0.01 to -0.15, indicating that the performance disadvantage of the experimental group was getting bigger, but it was still tiny, and the performance difference with the control group was still not significant (T = -1.58, p > 0.05). Further Verification and Discussion of Experimental Results This study indicates no adverse effect on student performance in this experimental school due to the large number of P.E. teachers being used as head teachers. Compared with previous theoretical discussions, this study was based on a relatively rigorous ex- perimental design, which provided a scientific basis for answering the question “Is it reliable for P.E. teacher to serve as a head teacher?” However, as some scholars have pointed out, although experimental research can accurately assess intervention variables’ effects and make causal inferences, it is challenging to demonstrate educational prac- tice’s richness (Lather, 2004). Although we have evaluated the effect of P.E. teacher as a head teacher through experimental research, we still have no way to answer under what circumstances and why P.E. teacher as a head teacher will help students grow? In response to such problems in social science research, researchers are paying more atten- tion to the application of mixed-method research. It is hoped that through the compre- hensive application of quantitative research and qualitative research, the advantages of both can be fully utilized to provide more robust evidence for research problems (Cre- swell & Clark, 2017). While implementing the experiment, this study also collected relevant qualitative data to verify the experimental results’ reliability further. Before and during the experiment’s implementation, we conducted interviews with school-level leaders of the experimental school, P.E. teacher as a head teacher, and randomly selected students through semi-structured interviews. The interview’s main questions focused on the school’s class management system and measures, the work mode of the P.E. teacher as a head teacher, and the effectiveness of class management work. The basic situation of the interviewees is shown in Table 2. Through such interviews, we hope to characterize further the work characteris- tics and internal mechanism of P.E. teachers as head teachers. In fact, not many schools use P.E. teachers as head teachers on a large scale like the experimental school ob- served in this research. There are many reasons why this school can do this and achieved good results: First, the school does not treat P.E. teachers differently in terms of management philosophy. It fully trusts P.E. teachers and provides them with opportunities to manage classes to achieve better development. P.E. teacher was initially used as a head teacher to solve the head teacher shortage caused by female teachers’ pregnancy and childbirth. In the beginning, the school was under much pressure. Fortunately, the initial attempts have achieved good Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 957 Table 2. Basic Situation of Interviewees. Serial Number Identity Description Interview Time XLD01-03 School Leader Including the school principal, the deputy principal in charge, and the school director Completed many times. It takes about 40-80 minutes per person, for a total of about 160 minutes. BZR01-11 Head Teacher A physical education teacher serv- ing as a head teacher 20-30 minutes per person, totaling about 270 minutes. Some of the interviewed class teachers provided written materials. XS01-18 Student Six people were randomly inter- viewed in each grade, from the first to the third grade. 10-15 minutes per person, about 200 minutes in total. results. This makes us more confident in appointing P.E. teachers as head teachers, from the initial passive response to the active arrangement. On the one hand, it solves the problem of head teacher shortage; on the other hand, it also dramatically mobilizes PE teachers’ enthusiasm to work and provides more for the development of “non-core subject” teachers, including PE teachers. Letting all P.E. teachers serve as head teach- ers has become routine management of head teachers in our school. (XLD01) In 2020, the first pacesetter head teacher selection, the school had a total of seven head teachers selected, of which there are four P.E. teachers. These P.E. teachers stood out from head teachers’ work and become role models for head teachers throughout the school. (XLD03) Second, this school also adopts a series of management measures such as for- mulating and implementing the head teacher work standards, establishing head teacher work files, forming a class management and work team led by the chief head teacher and strengthening head teacher work evaluation and incentives to ensure that all head teachers can complete their work tasks with high quality. In the long-term management practice, we have realized that which subject the head teacher teaches is not a decisive factor in determining the head teacher’s perfor- mance. Instead, it needs to rely on a complete set of head teacher management systems so that anyone can achieve the expected results in the position of the head teacher. Re- garding the P.E. teacher as the head teacher, in terms of system design, we strive to ensure the head teacher’s core position in the class management process and give the head teacher greater weight in class management. Simultaneously, to prevent head teachers from using their powers to allocate more time to their subjects, in the design of the incentive system, we adopt a way of rewarding the team and not individuals for class management. That is, no matter how good the head teacher’s subject is, it is use- less. Only when the class work is promoted as a whole, and the students develop in a balanced manner in all aspects, the class management team will be rewarded. (XLD01, XLD02) Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 958 We attach great importance to the regular management of head teachers. Since the teachers in our school are relatively young, they generally have the problem of in- experience in class work. In response to this, on the one hand, we adopt the old- fashioned and model-setting approach to promote the growth of head teachers. On the other hand, we have established a complete standardization process for head teacher work to ensure that no matter who serves as a head teacher, we will ensure the “bottom line” as long as we follow this standard” achievement. There will be no severe devia- tions in class management due to individual differences in head teachers. (XLD03) Third, the school organized a large number of targeted training so that P.E. teachers could obtain the support of relevant management knowledge and skills through learning and training before and after taking on the head teacher position. In addition to regular full-staff training and expert lectures, we will implement the “Head teacher Qinglan Project” in a voluntary and designated manner within one month of the beginning of each new school year, based on the configuration of the class management team. Through targeted assistance from experienced head teachers, we can improve young head teachers’ working abilities and accelerate their professional growth. P.E. teacher will encounter various problems in the actual class management work. The school has a dedicated person to collect the difficulties and confusions en- countered by head teachers in class management by grades, summarize and sort out common problems; use head teacher studios, seminars, and other forms to conduct dis- cussions. In this way, the head teacher can effectively solve the problem through multi- party consultation. (XLD03) Finally, in the field investigation process, we also found the unique phenome- non of P.E. teachers as head teachers mentioned in the previous literature. For example, we found that the classes managed by P.E. teachers pay more attention to sports activi- ties, the ways of teacher-student interaction are more flexible and diverse, and the class atmosphere and teacher-student relationship are more harmonious (XS01-18). This means that in addition to grades, a P.E. teacher acting as a head teacher can also bring more benefits to students for all-round development. This may also be the reason why the P.E. teacher’s class performance as a head teacher did not fall behind (Zhou et al., 2018). Children like sports. As a head teacher, P.E. teacher makes it easier to give play to their professional skills and talents, win the recognition and love of children, and create a good teacher-student relationship and class atmosphere. (BZR03, BZR05) P.E. teacher as a head teacher has advantages. Because P.E. teacher does not need to correct homework, the pressure of schoolwork is not as tremendous as the core subject teacher. This gives us more energy to pay attention to students and put more time and energy into class management. (BZR01, BZR02, BZR11) P.E. teacher serves as a head teacher because it rarely forms a competitive re- lationship with other teachers in performance appraisal, appraisal, and title promotion, so it is easier to coordinate the teacher’s relationship. Moreover, because P.E. teacher is relatively abundant in time and energetic, she/he often invests more in home-school cooperation. Over the years, no one of our school’s parents questioned the P.E. teach- Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 959 er’s role as a head teacher, and parents have highly recognized this management measure. (BZR01-08, XLD03) These survey results further explain why P.E. teacher serves as a head teacher and why it does not cause students’ academic disadvantages. At the same time, it also shows to a certain extent that P.E. teacher has unique advantages when engaged in class management. However, since we failed to measure the teacher-student relationship and class atmosphere during the experiment, we can only obtain empirical observation re- sults at present. More detailed studies in this area are needed in the future. Conclusions and Suggestions The most critical finding and conclusion of this research are that a P.E. teacher serving as a head teacher will not affect students’ academic performance. Not only that, in terms of promoting the overall development of students, may P.E. teacher has more advantages as a head teacher. Our study provides scientific evidence for the discussion of general topics and improves the head teacher’s configuration and management. First of all, at the conceptual level, prejudice and discrimination against “non- core subject” teachers, including P.E. teachers as head teachers, should be eliminated. Fundamentally speaking, the reason for this understanding is mainly due to the one- sided pursuit of academic performance. In management, the school should adhere to the correct teaching concept, strengthen the communication and exchange with parents, guide the parents with correct educational concepts, do an excellent job of clearing and explaining, and dispel unnecessary parents’ anxiety. Second, optimize the head teacher management to provide a good atmosphere and environment for P.E. teachers to serve as a head teacher. This research has proved that who is the head teacher may not be an essential issue. The critical question should be how to make anyone in the head teacher position indeed do an excellent job as a head teacher and grow. In this study, the experimental school has ensured the head teacher’s management work’s quality and effectiveness through training, incentives, and system construction. This may be a useful experience worth learning from. Third, give full play to the role of “non-core subject” teachers in educating people and realizing their work’s value. This requires appointing “non-core subject” teachers like P.E. teachers as head teachers and giving full play to these subject teachers’ expertise. This enables them to use more colorful class management methods to create a united and progressive class atmosphere, achieve the educational goals of establishing morals and nurturing people, and promote students’ all-round development. Bai et al. Reliability for Physical Education Teacher to be A Head teacher. Vol.7, No. 2, 2021 960 References Angrist, J.D. & Pischke, J.S. (2009). Mostly Harmless Econometrics: An Empiricist’s Companion, Princeton: Princeton University Press, pp9-pp18. ISBN: 978-0-691-12034-8. Chen, X. (2014). A brief analysis of discrimina- tion against physical education teachers. Sports Culture Guide, 32(12):122-125. [Chinese] DOI: https://doi.org/10.3969/j.issn.1671- 1572.2014.12.032 Cheung, A.C. & Slavin, R.E. (2016). How methodological features affect effect sizes in education. Educational Researcher, 45(5):283-292. https://psycnet.apa.org/doi/10.3102/0013189 X16656615 Cohen, J. (1992). A Power Primer. Psychology Bulletin, 112(1):155- 159. https://psycnet.apa.org/doi/10.1037/0033- 2909.112.1.155 Creswell, J.W., & Clark, V.L.P. (2017). Design- ing and conducting mixed methods research (3rd edition). Sage publications. ISBN: 1483344371. Gong, W., & Zeng, X. (2020). The feasibility analysis of a physical education teacher’s work as a head teacher from the perspective of core literacy. Contemporary Sports Tech- nology, 10(12):164+166. [Chinese] DOI: https://doi.org/10.16655/j.cnki.2095- 2813.2020.12.164 Kolen, M.J., & Brennan, R.L. (2014). Test equating, scaling, and linking: Methods and practices. Springer Science & Business Me- dia. ISBN: 978-1-4939-0317-7. Lather, P. (2004). Scientific research in educa- tion: A critical perspective. British Educa- tional Research Journal, 30(6):759-772. DOI: https://doi.org/10.1080/01411920420002794 86 Qi, K., & Wang, Z. (2020). Analysis of physical education teachers’ status quo in primary and middle schools as “class teachers”. Chi- na Economist, 32(7):193-194. [Chinese] https://www.cnki.com.cn/Article/CJFDTotal -JJSS202007099.htm Shi, X. (2021). Can a non-core subject teacher serve as a homeroom teacher? Discussion on the dispute between core and non-core sub- ject teacher as homeroom teacher. Science Insights Education Frontiers, 8(1):989-1000. https://doi.org/10.15354/sief.21.or003 Slavin, R.E. (2020). How evidence-based reform will transform research and practice in edu- cation. Educational Psychologist, 55(1):21- 31. DOI: https://doi.org/10.1080/00461520.2019.1611 432 Wang, J., Yu, L., Xiong, W., & Qi, X. (2009). The influence of parent-child, peer, teacher- student relationship on junior high school students. Journal of Psychological Science, 32(6):1439-1441. [Chinese] https://www.cnki.com.cn/Article/CJFDTotal -XLKX200906046.htm Zhao, Q. (2020). “Sports teacher was com- plained about being a class teacher,” the Ministry of Education uttered an interpreta- tion. Tencent News. [Chinese] https://xw.qq.com/cmsid/20201017A0CT9I0 0?f=newdc [2020-11-25] Zheng, H., Wen, Z., & Wu, Y. (2011). Selection and analysis of commonly used effect sizes in psychology. Advances in Psychological Science, 19(12):1868-1878. [Chinese] http://journal.psych.ac.cn/xlkxjz/CN/Y2011/ V19/I12/1868 Zhou, S., Gu, H., & Yao, J. (2018). From “hard study” to “skillful study”: Analyzing the key factors affecting students’ academic perfor- mance-an empirical study based on the mon- itoring data of 262,245 students’ academic quality in Jiangsu Province. Primary and Secondary School Management, 32(11):39- 43. [Chinese] Received: 26 February 2021 Revised: 01 March 2021 Accepted: 09 March 2021 https://doi.org/10.3969/j.issn.1671-1572.2014.12.032 https://doi.org/10.3969/j.issn.1671-1572.2014.12.032 https://psycnet.apa.org/doi/10.3102/0013189X16656615 https://psycnet.apa.org/doi/10.3102/0013189X16656615 https://psycnet.apa.org/doi/10.1037/0033-2909.112.1.155 https://psycnet.apa.org/doi/10.1037/0033-2909.112.1.155 https://doi.org/10.16655/j.cnki.2095-2813.2020.12.164 https://doi.org/10.16655/j.cnki.2095-2813.2020.12.164 https://doi.org/10.1080/0141192042000279486 https://doi.org/10.1080/0141192042000279486 https://www.cnki.com.cn/Article/CJFDTotal-JJSS202007099.htm https://www.cnki.com.cn/Article/CJFDTotal-JJSS202007099.htm https://doi.org/10.15354/sief.21.or003 https://doi.org/10.1080/00461520.2019.1611432 https://doi.org/10.1080/00461520.2019.1611432 https://www.cnki.com.cn/Article/CJFDTotal-XLKX200906046.htm https://www.cnki.com.cn/Article/CJFDTotal-XLKX200906046.htm https://xw.qq.com/cmsid/20201017A0CT9I00?f=newdc https://xw.qq.com/cmsid/20201017A0CT9I00?f=newdc http://journal.psych.ac.cn/xlkxjz/CN/Y2011/V19/I12/1868 http://journal.psych.ac.cn/xlkxjz/CN/Y2011/V19/I12/1868 OriginalArticle-JijunYao-BECE_title_March2021 OriginalArticleArticle-JijunYao-BECE_MaintextMarch2021