Why should one take into account both the matura exam result and the EVA indicator?
The mean exam result and the EVA, that is the teaching effectiveness indicator, are complementary measures. Together, they provide more comprehensive information about a school than any of them separately. As a consequence of taking into account of both the exam result and the EVA indicator, the school result is presented on a two-dimensional coordinate system. Due to the statistical uncertainty, estimates of indicators of a school’s place are presented in the form of ellipses. The size of the ellipsis graphically represents the degree of that uncertainty. The more exam results are incorporated into the calculations, the lesser the uncertainty and, therefore, the smaller the ellipsis.
A description of the place of the school (ellipsis) in the coordinate system (the exam result, the EVA) may be facilitated by distinguishing of several reference points.
- Neutral schools. Lower secondary schools, in which we record both the average exam results against the national figure and average effectiveness.
- Schools with high exam results and high effectiveness measured by the EVA (upper right-hand quarter).
- Schools with high exam results and low effectiveness measured by the EVA (lower right-hand quarter).
- Schools with low exam results and low effectiveness measured by the EVA (upper left-hand quarter).
- Schools with low exam results and low effectiveness measured by the EVA (lower left-hand quarter).
Besides the main types, one can observe intermediate types: schools with average results and low/high EVA and schools with average effectiveness (EVA) and low/high exam results. in those cases, the ellipses of the schools are located on the vertical or the horizontal axis, respectively.
The above points of reference are to help in interpretation of the school’s place in the coordinate system, rather than categorisation of schools.
How to read the graphs?
To facilitate statistical interpretation of the position of a lower secondary school, two ellipses have been plotted on the graph. The smaller, dark grey, identifies the area where 50% of schools are located. The second ellipsis, light grey, demarcates the area, where 90% of schools are located. Point (100;0) is the centre of symmetry of the ellipses.
Example 1.
Lower Secondary School A. Maths and Sciences part
The position of the green ellipse on the graph indicates that we are dealing with a neutral school (Maths and Sciences part of the exam). This is what schools whose position in the coordinate system is close to the point (100;0) will be called. If the confidence interval (green ellipse) covers point (100;0), we are dealing with that type of school. A neutral school is an institution statistically average. To avoid, however, expressions like “average, mean”, we propose the term “neutral school” for schools with average exam results close to the national mean and the EVA indicator close to zero. Neutral schools are the most numerous category of lower secondary schools. It is so, for both the exam result, and the EVA indicator most often take values close or not so distant from the mean.
Example 2.
Schools B and C. Maths and Sciences Part
How do schools B and C differ? Final results. The averages for the lower secondary schools are in terms of exam results distant by about 10 points (2/3 of standard deviation). How are they similar? Above-average effectiveness of teaching measured by the EVA indicator. We can say so, as the confidence intervals for both schools are located above the horizontal line which means the zero value of the EVA (horizontal axis). The past ways of analysing exam results would place the schools in distant stanines and we would never think that the institutions may have something in common. Introduction of the EVA dimension enabled us to see something that was hidden from an observed not equipped with the appropriate statistical instruments.
Finally, we would like to warn the users of our website that the following messages may appear for some lower secondary schools:
| There appears a graph, underneath the following comment | In the combined database of results of the lower secondary school exam and the primary school leaving test, more than 10% of data are missing. It may result from problems in merging of the results of the exam with the test. Therefore, determination of the school’s position on the graph may be less precise. |
| There appears a graph, underneath the following comment | In the combined database of the lower secondary school exam and the primary school leaving test results, we have results from 2 years only. therefore, determination of the school’s position on the graph may be less precise. |
| No graph, only the comment appears | In the combined database of the lower secondary school exam and the primary school leaving test results, there are no data of that lower secondary school. |
| No graph, only the comment appears | In the combined database of the lower secondary school exam and primary school leaving test results, we have less than 30 results for that lower secondary school. |
| No graph, only the comment appears | In the combined database of the lower secondary school exam and the primary school leaving test results, there are no data of that lower secondary school from the last year. |
