Issues in Interdisciplinarity 2019-20/Evidence: Is private school really better than public school?

Introduction
It is a common, universal belief that private school provides a higher quality of education than public school; this assertion serves as one of the main justifications for parents choosing a private education for their children. This chapter aims to discuss the validity of this claim, by presenting conflicting evidence and examining its veracity from multiple disciplinary perspectives closely linked to education studies, in order to bring attention to potential issues encountered when conducting interdisciplinary research in this field.

Ancient and modern philosophers have identified varying purposes of education. While a functionalist view suggests education equips students with the right qualities and skills to function in prevailing socio-economic conditions, the traditional platonic view theorizes education's broader goal to help one's soul ascent from the cave of ignorance. Dissimilar education philosophies and ideologies contribute to differences in operations and subsequent educational outcomes in private and public schooling.

The origin of private education lies in religion, taking heavy influence from Catholic schooling. Gradually, private schools evolved from the classic curriculum to provide an alternative to government-run public schools. However, the claim that private education is superior to that of public school was not backed by empirical evidence until 1981 when Coleman published a pioneering study that started the public-private debate. Through quantitative research, he reached the controversial conclusion that private schools provided a more effective education and experienced less racial segregation than public schools. This led to numerous follow-up studies; some criticized Coleman's methods and conclusions, while others asserted his findings. Currently, there is still a notable lack of consistency in scientific research regarding this topic.

Disciplinary Approaches
In economics, the most common measure of effectiveness in education is academic achievement, particularly in key disciplines such as mathematics and English. Attendance and failure to complete high school, progress into further education, and performance at university and in the labour market are also indicators of quality of education.

Research is conducted through quantitative methods, analyzing cross-sectional data to compare performance across schools. A standard method of comparison involves calculating predicted scores an average public school student would attain at private school and comparing them to actual past results at public school. Ways of controlling external factors in econometric models include grouping students into socioeconomic status (SES) levels through surveying parents' income, level of education and available educational resources at home, and considering elements such as race/ethnicity and disabilities.

Although results are mixed, there is a general consensus that private schools achieve better results overall, but it cannot be presumed that this implies direct causation. One study suggests that the selective enrolment of high-level SES students at private school results in a higher proportion of students better suited to conventional education methods, thus possessing a naturally higher potential for academic achievement. This highlights the uncertainty regarding the degree to which schools influence the performance of their students. Some criticisms blame the lack of research examining progress over time; however, the inability to arrive at a universal conclusion using econometric evidence can be traced to several larger issues, such as the complexity of individual school systems, the influence of non-quantifiable factors and widely differing research methods.

Sociology examines the interaction between socio-economic factors, such as  family background, and academic performance in schools. The evidence is congregated upon both external and internal issues of social class, gender, and ethnicity. Social scholars highlight that the benefits of private schools are recognized through the inherited experience and funding of families. They argue that disparities in educational performance were not affected by the type of school children attended or school differences between social classes, but rather by the students’ background, individual aptitudes, and gender.

Quantitative research is conducted to determine the number of people who share the same views on the question being asked. This research incorporates an interview method that investigates the issues affecting the performance of students. There is compelling evidence that students from low-income families with African or Caribbean ethnicity perform worse than students from other backgrounds. Family income also influences educational success, as evidenced by a statistical analysis of examination results. While working-class girls perform better than working-class boys, they still lack behind middle school children. Sociologists conclude that scholastic accomplishments depend on students’ levels of physical and cultural capital.

The studies reveal some limitations. Sociologists cannot state confidently on what is the particular causal effect of students attending private schools due to the high entry-level of students going to private schools compared to public schools. Even where substantial evidence is evaluated, the omission of unobserved differences can still be biased in estimating the effects.

Educational psychology investigates how academic performance is affected by factors such as well-being. Psychologists gather empirical evidence from quantitative questionnaires, they also devise tests and criteria to measure components of well-being. The strength of evidence is checked by its statistical significance, with measurements such as p-value and standard deviation.

Whether students in private schools have better or poorer well-being is contested. A study on the mental health of Chinese private high school students found that they face significantly higher levels of negative emotions such as compulsion, depression, hostility, and paranoid ideation than their counterparts in public schools. Another study, however, found that anxiety and fear levels of Chinese high school students did not differ between private and public schools. The impact of private school is less significant than that of gender, family, and culture that sociology tries to tackle. Moreover, the relationship between well-being and academic performance is also complex. The positive relationship between well-being and academic is supported by a wealth of studies. But scholars also noticed a trade-off between education performance and well-being in many private schools, which can, in turn, impede academic achievements.

The contradicting results show that psychologists use varied methods to study mismatched aspects of well-being and measure discrepant forms of academic performance, thus they are supported by divergent evidence. Some evidence is weak due to the unreliability of self-completed questionnaires and the relativity of self-reported emotions - respondents may be dishonest and they can have vastly different interpretations to the same number when asked to rank emotions. As Richard Popp argues, emotion is a socio-cultural product; thus, sociology can help explain the larger forces that contribute to inconsistent understandings and presentations of well-being. Meanwhile, unclear causal and correlation mechanisms require econometric thinking to elucidate how well-being affects and is affected by academic performance.

Conclusion
After exploring the topic of public versus private school from several disciplinary viewpoints, it becomes clear that current monodisciplinary approaches are not sufficiently able to deal with problems encountered in research. The complexity of education systems requires a comprehensive approach beyond linear analysis, combining quantitative and qualitative research methods across multiple fields within Education Studies to overcome their individual limits.

However, current research shows a lack of coherency even within their own disciplines, largely due to varying research methods. The resulting inconsistent and contradicting conclusions create difficulties when applying interdisciplinary methods, which highlights the need for standardisation and further research into key elements of education to reach a valid, reliable and accurate conclusion regarding the long-standing debate of private versus public schooling and beyond.