Six full rounds of PISA research have now taken place, and seventh round is ongoing.  The main study areas have been literacy, math and science twice each. Each round also provides a survey for all participating schools. In the form of a school questionnaire, the principals of the schools participating in the PISA study are asked about background factors related to the organization of school education, school management practices and study conditions. It is possible to identify the material from schools that have participated in research in several rounds of research. This paper focuses on these conditions of the PISA study in 2006 and 2015 and the changes that took place over the nine years. Also, the differing backgrounds of the schools and their profiles and their potential connections with students’ abilities are the focus of this study.

Students with high socio-economic background are better off at school when compared with their peers with lower background, even though the school has its own equalizing effect (Dowey & Condron, 2016). In the PISA 2012 survey, on average, half of the fluctuation in the competence of mathematical literacy was related to the socio-economic status of the school (OECD, 2016b). The socio-economic profile of the school is based on the average socio-economic background of the pupils and has been found to be strongly related to the knowledge of school pupils (eg Marks, 2005, Schmidt & Lang, 2015). In this study she school's socio-economic status acts both a grouping variable of schools and a strong background variable indicating schools’ change and development.

A positive atmosphere supports and strengthens collaborative learning, cohesion, respect and mutual trust (Thapa et al., 2103). The atmosphere is also linked to the sense of belonging in school that is generally weakened in Finland and OECD countries on average (OECD, 2017). School satisfaction has been studied to be directly related to learning outcomes (Samdal et al, 2004, Seligson, Huebner & Valois, 2005). The school's atmosphere is examined in this article by the PISA indices based on the Rector's estimates of both the students 'and teachers' everyday activities.

School management is a key factor behind school work and learning, which has a "catalyzing" effect on learning (Bush & Glover, 2014).  In this article, school management is understood as the reflection of school work over the long term. In this case, conclusions can also be drawn from time to time backward. The methods of management and the activities involved are charted by the rector himself and the answers are built to indicate the school management culture.

The focus of this study will be on changes in the school environment, teaching resources, school climate and leadership. Are there any factors for which schools could be grouped into groups of different profiles? What kind of changes have occurred in schools of different profiles during the research years? What kind of connections are the background factors of the school to the pupils' literacy or study atmosphere? The research task will form the following research questions:

1. How and with what factors are the backgrounds of the schools described?

2. What kind of groups of schools can be formed according to schools’ average performance in science and socioeconomic status and their change?

3. How do schools’ resources, atmosphere and management culture differ between groups?

4. What are the major overall changes in schools between 2006 and 2015?

This study is based on the basis of the statistical analyzes used in the PISA study (OECD 2009, OECD 2016a). School questionnaire responses are treated as indices, scaled to OECD averages, and reported using the Weighted Likelihood Estimates (WLE). OECD average is standardized to zero and standard deviation is one. Thus, the index calculated for a single school can be reliably compared not only in relation to each other, but also in relation to the OECD level. The schools were divided into groups using SPSS grouping analysis using the K-Means method. The schools were divided into four distinct groups that are mainly used for presenting the changes and the interpretations are mainly descriptive. Differences in mean values are examined between the two groups by a T-test or the Post-hoc test of the variance analysis by the Scheffe method when looking at differences between several groups. Correlations are calculated by Spearman correlation coefficients. These are utilized as background data, but the findings of 35 observations are often insufficient to find statistically significant links or differences. Hence, the analyzes are primarily based on qualitative interpretations of trends between the years of research and the comparison of the OECD indices between schools and the four school groups formed for this purpose. The research material in question thus encompasses the answers of 35 school principals to PISA 2006 and PISA 2015 school surveys. This means that averages of pupils' answers are brought to school-level material to represent school knowledge or student background variables. The ESCS index (Economic, Social and Cultural Status) describing the socioeconomic and cultural position, the external motivation of science, and the average scores of school pupils in the PISA trials of reading, mathematics and science in 2006 and 2015 are utilized as aggregate variables.

Schools could be grouped in four distinct groups according to their students’ aggregated science achievement and its change between the assessment years 2006 and 2015 and schools’ socioeconomic status and its change. The groups were formed as following: Group 1 (named as Decliners) consisted of eight schools whose science mean score was weakened on average -62 points, and this group of schools students’ average ESCS index was also declined. Group 2 (named as Constant low achievers) consisted of 15 schools whose science means score was low in both years of assessment, even though its mean ESCS-index increased. Group 3 (named as Gainers) consisted of four schools, whose science score and mean ESCS-index was increased the most from year 2006 to 2015. Group 4 (named as Constant high achievers) consisted of eight schools, whose science score and ESCS-index averages were very high in both assessment years. Do schools change? In general, the studied schools’ resources and socio-economic status have changed in better direction, but the changes are mostly rather small. Two-thirds of the schools belonged to groups that have changed little with regard to the factors studied here. Eight schools belonging to group 3 are permanently at a very good level with all indicators. In the other groups, individual changes in schools have occurred a little more, but no common factors, besides the decline in science performance, can be found. The factors related to school resources, atmosphere and leadership culture and their changes will be presented according to the four groups of schools.

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