Research on determinants of school and classroom variation in

In this section, we provide a brief overview of research on factors influ- encing variation between schools and classrooms.

3.3.1 Selection of students to different schools

Previous research has shown that the most important determinant of school level performance differences is the composition of the schools’ student body with respect to social and ethnic background, and with re- spect to previous level of performance (e.g. Coleman, et al., 1966; Jencks & Mayer, 1990; Thrupp & Lupton, 2006; Yang, 2003).

Explicit selection of students into schools on the basis of previous per- formance is an important factor in causing school differences. Thus, school systems which use organisational differentiation to track students into academic and non-academic schools are characterised by very substantial school performance differences, which may amount to 40–50% of the total amount of performance differences (see, e.g., OECD, 2013; Yang, 2003). Germany and Austria are two examples of countries with such organisational differentiation. In the 1960s and 1970s, the Nordic coun- tries abolished organisational differentiation and introduced comprehen- sive compulsory schooling; so, in these countries, school performance differences are smaller and typically account for less than 10% of the total performance variation. However, even school differences of this magni- tude may be of substantial importance (e.g. Yang, 2003).

Given that students often attend neighbourhood schools, the socio- economic and ethnic composition of schools tends to reflect the socio- demographic characteristics of the neighbourhood that the school serves. Therefore, residential segregation with respect to socio-economic back- ground and ethnicity affects school performance differences. If students and parents are allowed free school choice, this may also affect school perfor- mance differences. Students sorting themselves into schools on the basis of socio-economic and ethnic factors may cause school performance differ- ences to increase over and above the differences caused by residential seg- regation. However, students sorting themselves into schools on the basis of ambition and ability may reduce the effects of residential segregation but increase segregation on the basis of performance (Gustafsson, 2006).

There is quite a rich body of literature of international research on dif- ferent mechanisms of school segregation and their relative importance (see, e.g., Palardy, 2013; Sahlgren, 2013). However, results tend to be incon- sistent across studies, and so far little consensus has been achieved. The main reason for this is probably that the mechanisms to a large extent are specific to different cultures and school systems. This suggests that it is important to investigate these issues within the Nordic countries as well.

As has been described above, there have in Finland, Norway and Swe- den been reforms of the educational systems, which to a varying extent have allowed students and parents increased possibilities of school choice.

This may influence the amount of school differences, and particularly so in urban areas where there are real possibilities of choice.

If attendance at different schools is determined by residential segrega- tion and/or school choice, it may be expected that this will cause differ- ences between schools with respect to the students’ socio-economic status (SES). Such differences will also be reflected in performance differences between schools, given the strong relationship between SES and perfor- mance, particularly at the school level (Sirin, 2005). These performance differences are likely to be observed primarily at the school level unless allocation of students to different classrooms is made on the basis of pre- vious levels of performance.

3.3.2 Classroom differences in performance

Previous research has shown that classroom differences in level of per- formance often are of substantial magnitude and that they often are larger than school differences (see e.g., Creemers & Kyriakides, 2008). While classroom differences may be due to the sorting of students into different classes, they also may reflect differences in quality of instruction and dif- ferences between classrooms with respect to teacher–student relations, for example. Thus, the determinants of classroom differences in perfor- mance are likely to differ from those causing differences in level of per- formance between different schools.

Furthermore, many studies confound variation between schools and classrooms, by not separating their relative contributions. This is some- times due to the fact that this is not possible because it requires that the different schools be represented by two or more classrooms and also that the classroom to which each student belongs is correctly represented in the data. When school and classroom variance is confounded, the results typically are reported in terms of school differences. However, such esti- mated school differences may to a considerable extent reflect classroom differences. Confounding of the two sources of variation may thus system- atically bias the findings from studies on school variation.

3.3.3 Research questions

The TIMSS and PIRLS data include information about different character- istics of the schools, such as location (urban/rural) and students’ socio- economic background. This information can be used to investigate the different mechanisms behind school variation more closely. Thus, school choice is mainly an urban phenomenon, and the effects of school choice can therefore primarily be expected to be seen in urban areas. Residential segregation is also primarily an urban phenomenon, and it may be ex- pected that this is a more important factor for students in lower grades than in higher grades. Comparisons of differences in the amount of ob- served school performance differences in urban and rural schools for Grades 4 and 8 in the three countries may therefore be a way to investi- gate the impact of school choice and residential segregation.

The following research questions will be focused upon:

• What differences are there in the magnitude of school and classroom performance differences for Grade 4 and Grade 8 in Finland, Norway and Sweden?

• What differences are there in the magnitude of school and classroom performance differences in urban and rural schools in Finland, Norway and Sweden?

• To what extent are school and classroom performance differences related to students’ SES in Finland, Norway and Sweden?