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2018 International Schools Assessment Report
By Jacob Martin, Director of Teaching and Learning

This article looks at the International Schools Assessment (ISA) data for the 2018-2019 academic year. Every October our students in Grades 3, 5, 7 & 9 take the ISA tests and we use the results of these to examine the progress of students as they move through the school. The ISA data over the last nine years has been collated to allow us to look at the growth of skills in the cohort as a whole or in individual students. We can also compare our performance with other like schools and a total group of over 500 international schools.

The cohort’s progress is analysed in the areas of Mathematical Literacy, Reading and Writing, and we are delighted that we see a strengthening in the results of our students across all areas as they progress through ISZL.

Interpreting the graphs

The graphs used in this report are of the box and whisker variety. The blue dashed lines show the average results of a group of over 500 international schools taking the ISA tests in any given year. The green boxes show the results of ISZL students in that year. Box plots are graphical representations of data, and are used here to describe the variation or spread of ISA scale scores within a particular cohort. A large box indicates that there is great variation in the scores. The length of the box represents the difference between the 25th and 75th percentiles: the middle 50% of scores are within this box. The point to which the line extends below the box indicates the 5th percentile, and the point to which the line extends above the box indicates the 95th percentile. These lines further indicate the spread of scores, as longer lines suggest more extreme scores in that direction. The median value for the group is the horizontal white line. The median average is used as opposed to the mean or modal averages as it is less affected by the outliers within a group and therefore gives a better average idea of the performance of the group in question.

Progress in Mathematics

What is being measured in Mathematics?

The ISA test is attempting to measure both mathematical content, which has been covered, but also the skills in applying this knowledge. The test is based upon the PISA test ¹ used by national governments and international educational organizations. The ISA scale can be converted to the PISA scale which allows us to compare with other national systems and other international schools.

Although more data is required to identify a longer-term trend the signs are very healthy for the improvement of mathematics. Two significant things can be identified from the 9 years of Data we now have. Firstly, the variation in Mathematics performance across all schools in the ISA cohort is small compared to the other skills. Secondly, the ISZL cohorts usually begin below the Grade 3 average for like schools and this has been the case for the last three years but they progress more quickly and further over the course of the programme and by Grade 9 we have a significantly stronger mathematical performance than the average ISA score. Most of our students performing better than the average ISA performance by the beginning of Grade 9. We believe that by focussing on mathematical mindsets and skills in problem solving early on in our programme we are better preparing students for the challenges of senior Mathematics courses and ultimately producing better mathematical thinkers.

Progress in Reading

Reading in the ISA test is defined as “understanding, using, reflecting on and engaging with written texts, it is designed to look at decoding and literal comprehension in a full range of situations in which reading plays a role for students from Grade 3 to Grade 10.

Since 2012 the Grade 3 cohorts have started close to the 50th percentile of the ISA cohort, this is evidence of a sound reading programme in the Early years and grades 1 and 2. Between grade 3 and grade 5 there is evidence of growth in the reading skills of all of our students due to a focus in the curriculum on literacy skills. Between grade 7 and grade 9 the median continues to rise and by grade 9 the significant majority of the ISZL cohort are above the 75th percentile of the ISA cohort. This represents a significant growth in the reading ability of our student compared to the growth in the rest of the ISA cohort.

Progress in Narrative Writing

The first writing task (writing task A) looks at the students narrative and reflective writing. There are three aspects that are looked at Language, Spelling and Content

The development of writing skills is consistently strong at ISZL however the range of the skills in narrative writing in Grade 3 are significant and are usually measured as being lower than the norm in Grades 3 and 5. The subsequent development in the writing skills of students is well above the development expected by the ISA norm after Grade 5.

Progress in Exposition Writing

The second writing task (writing task B) looks at expositional and argument writing with three aspects namely content, language and organisation.

The growth in skills for expositional writing at ISZL is also very strong. The cohort growth is significant and although we have a wide range in Grade 3 as with Narrative writing we end up with a really strong performance across all our students. By grade 9 approx. 75% of our students are above the 50th percentile in the ISA cohort.

Overall, we are delighted with the progress shown in our students throughout their journey at ISZL.



[1] OECD Programme for International Student Achievement (

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