About me
Jöran Petersson has a PhD in mathematics education (2017) and is lecturer and postdoctoral researcher in mathematics education. He also got a master (licentiate) in mathematical systems theory and optimization from the Royal Institute of Technology, Stockholm (1999) and a diploma as upper secondary school mathematics and physics teacher from Linköping University (2004). He has worked with research and development as mathematician in industry (sensor signals and control systems) and insurance business (19992002). He has taught several years in secondary school in classroom and as distance teacher via internet (20022007) and as university lecturer in mathematics for engineering students (19931998) and mathematics education for teacher students (since 2007). Please follow the link < http://researchdatabase.su.se/converis/portal/Person/136285 > (Profile in research database) for viewing Jöran's publication list etc.
Teaching
I teach mathematics education mainly for secondary school teacher students but sometimes also for primary school teacher students. I also supervise theses in first and second cycle.
Research
Presently Jöran is a post doctor researcher in the FoNSproject at MND together with professor Paul Andrews and doctor Judy Sayers. In this project he studies how concepts in Foundational Number Sense, FoNS, are presented (by books, teachers and parents) for children in grade one in school.
Jöran's PhD in mathematics education (2017) was in the intersection of students having Swedish as a second language and students' use of mathematical concepts and he had Eva Norén as main supervisor. He has collected data from students' solutions on classroom tests and from interviews. In this research project one conclusion is that there is a need to see early and newly arrived immigrants as two groups having different challenges when being taught and tested in mathematical concepts in their second language: While newly arrived student are challenged by the new language, the early immigrants on average are more challenged with the mathematical content. A second conclusion is that there is a need in research to look at specific topics in mathematics for these student categories.
Jöran's licentiate thesis in mathematics (1999) was on designing an algorithm for the optimisation problem of fitting a sum of up to three exponential terms a_{i}*exp(b_{i}*t) to empirical data (a time series). This problem is difficult for two reasons, namely since exponential functions are nonlinear and since sums of exponential functions are strongly linearly dependent. This problem was solved by using algebraic methods to design a startup algorithm finding a nearoptimal solution and then finetune this solution using numerical methods. As a historical note, the idea behind the algebraic startup algorithm is the same as in methods used by astronomers in the 1700 for solving overdetermined systems of equations; namely to aggregate data into as many partitions as there are unknowns to determine and thus formulate a solvable system of equations. This research task in applied mathematics illustrates that solving a problem takes not only one branch of mathematics, but several branches, such as algebra, statistics and numerical methods working closely together. This aspect of learning to master a whole palette of mathematical tools certainly applies to teaching problem solving in school mathematics as well.
Publications
A selection from Stockholm University publication database
2018. Jöran Petersson. Nordisk matematikkdidaktikk, NOMAD 23 (34), 105122
The present study investigated how 259 Swedish, grade 9 students, of whom 90 had an immigrant background, achieved on twelve written test items in the content area of number. Four of the twelve test items required good knowledge of arithmetic syntax, such as when it was appropriate to apply orderofoperation rules and the associative and distributive laws of arithmetic operations. On these four test items, the mostrecently arrived students showed on average significantly more knowledge than the students who had immigrated when they were younger and had participated in Swedish schools for longer periods of time. The outcome suggests that these two groups of immigrant students in later school years should be considered as separate subcategories of secondlanguage students when it comes to teaching, assessment and research.

2018. Jöran Petersson. Nordic Research in Mathematics Education, 179187
The present study investigated how 259 grade 9 students solved two test items in algebra involving linear expressions. Some students were early or newly immigrated second language students in Sweden, The findings are based on a categorization of the students’ written responses. The results show that for the more advanced test item on linear expressions and unknowns, early arrived second language students achieved worse than newly arrived and other second language students with statistical significance, while there was a minor achievement difference when solving an elementary linear equation. The interpretation of the results is that the early arrived immigrants suffer from having larger parts of their mathematics education as second language students and thus struggle with advanced mathematics.

Article To halve a fraction2017. Jöran Petersson, Eva Norén. Education Inquiry
The present study investigated test responses from 259 immigrant and nonimmigrant school year 9 students in Sweden with the focus on how they solved two problems on fractions, one of them halving a fraction, in a test. The authors report three observations. Newly arrived second language immigrants seemed less likely to have the word ‘half’ in their Swedish mathematical vocabulary. Moreover, second language learners with longer experience of the new language connected the word ‘half’ with a division by two, but showed mathematical difficulties in correctly applying it to a fraction. A third finding was that the longer the experiences with Swedish school mathematics, the more likely both first and second language learners were to erroneously omit the percentage symbol, when choosing to use percentage representation of the fraction given in the test problem. The authors suggest seeing newly and early arrived second language immigrants as meeting different challenges. The newly arrived second language immigrants may know some mathematical concepts better and Swedish language less. In contrast the opposite seems to hold for second language learners with longer experience of the language of instruction.

2017. Jöran Petersson. Nordisk matematikkdidaktikk 22 (2), 3350
This study compares Swedish first (N=2 253) and second language (N=248) students' achievement in mathematical content areas specified by the TIMSSframework. Data on mathematics achievement from three national tests 20072009 in school year 9 are used. The present study found that the achievement difference between the mathematical content areas algebra and number was smaller for second language students than for first language students and this result holds with statistical significance (p=0.016). The same holds for algebra versus data and chance (p=0.00053). A hypothesis for further research is suggested; that students immigrating in late school years have contributed to the observed result by bringing experiences from other curricula into their new schooling.

2013. Jöran Petersson. Tintinism, 113120