Assessment for Learning – Making a Difference in Middle Years Mathematics A Keynote Address to MTANT14 by Professor Dianne Siemon RMIT University dianne.siemon@rmit.edu.au The curriculum anticipates that schools will ensure all students benefit from access to the power of mathematical reasoning and learn to apply their mathematical understanding creatively and efficiently. The mathematics curriculum provides students with carefully paced, in-depth study of critical skills and concepts. It encourages teachers to help students become self-motivated, confident learners through inquiry and active participation in challenging and engaging experiences. (ACARA, 2012, Mathematics Rationale) © Dianne Siemon It is through our assessment that we communicate most clearly to students which activities and learning outcomes we value (David Clarke (1988) © Dianne Siemon OVERVIEW • The nature and purpose of assessment • Assessment FOR Learning • The case of multiplicative thinking • AMSPP Priority Project • Reaching them and teaching them – Five essential feelings for success in the middle years (Sagor & Cox, 2004) © Dianne Siemon THE NATURE AND PURPOSE OF THE ASSESSMENT Scaffolding student learning is the primary task of teachers of mathematics. This cannot be achieved without accurate information about what each student knows already and what might be within the student’s grasp with some support from the teacher and/or peers. Assessment OF, Assessment AS and Assessment FOR Learning © Dianne Siemon Assessment OF learning is summative – it is used for reporting, selection and comparison purposes Topic Tests © Dianne Siemon Commercial Tests ‘for the Australian Curriculum’ For example: Assessment of Student Performance at Year 5 © Dianne Siemon QLD Department of Education (1991) Assessment AS learning is generally informal and relies on records of observation, performance, artifacts … Self and peer assessment Posters, projects, reports © Dianne Siemon For example, Olssen et al, (1994). Using the Mathematics Profiles © Dianne Siemon Assessment FOR learning requires assessment techniques that expose students thinking. Feedback BUT it also requires an interpretation of what different student responses might mean and some practical ideas to address the particular learning needs identified. © Dianne Siemon Assessment FOR learning is particularly important in relation to a relatively small number of ‘big’ ideas and strategies in Number, without which students’ progress in mathematics will be seriously impacted. • • • • • • Trusting the Count (end Foundation/mid Year 1) Place Value (end Year 2) Multiplicative Thinking (end Year 4) Partitioning (end Year 6) Proportional Reasoning (end Year 8) Generalising (end Year 10) Assessment for Common Misunderstandings Scaffolding Numeracy in the Middle Years (SNMY) © Dianne Siemon ASSESSMENT FOR LEARNING: Teaching informed by quality assessment data has long been recognised as an effective means of improving learning outcomes (e.g., Ball, 1993; Black and Wiliam, 1998; Callingham & Griffin, 2000; Clark, 2001). Typically, the tasks used for this purpose: • focus on what the student understands and can do (Darling-Hammond et al, 1995); • allow all learners to make a start, • accommodate multiple solution strategies; and • relate to the kinds of activities used in teaching and learning (Clarke & Clarke,1999; Callingham & Griffin, 2000). © Dianne Siemon Why is this important? Too many students are being ‘left behind’ in the middle years; Overcrowded, undifferentiated, often obscure mathematics curriculum; Need to support the growing number of out-of-field teachers of mathematics in more appropriate ways; and Need to challenge the pedagogical assumptions inherent in the represented or ‘packaged’ curriculum (e.g., texts). © Dianne Siemon THE AMSPP PROJECT – ROUND 1: The objectives of the Australian Mathematics and Science Partnership Program (AMSPP) are to: (i) build the theoretical and pedagogical skills of school teachers to deliver maths and science subjects; (ii) increase the number of school students undertaking maths and science subjects to Year 12; (iii) improve outcomes for these students; and (iv) encourage more students to study science, technology, engineering and maths (STEM) courses at university through innovative partnerships between universities, schools, and other relevant organisations. https://www.education.gov.au/australian-maths-andscience-partnerships-program © Dianne Siemon What we knew and what we had: Middle Years Numeracy Research Project (MYNRP) commissioned by DEET, CECV, AISV (1999-2000) – explored number sense, measurement & data sense and spatial sense in Years 5 to 9 using rich tasks and the Numeracy Profiles for Years 5 and 7 - identified multiplicative thinking as the area most responsible for the eightyear range in student mathematics achievement in the middle years (Siemon, Corneille & Virgona, 2001)* Scaffolding Numeracy in the Middle Years (SNMY) Linkage Project with the Departments of Education in Victoria and Tasmania (2003-2006) explored the development of multiplicative thinking in Years 4 to 8 using rich assessment tasks and Rasch modelling – confirmed MYNRP result, produced research-based Learning and Assessment Framework for Multiplicative Thinking (LAF) and two formative test options (Siemon, Breed, Dole, Izard & Virgona, 2006)* * Final Reports of both projects can be found on the DEECD website together with the SNMY resources © Dianne Siemon The Middle Years Numeracy Research Project (MYNRP, 1999-2001) 11.5 • • As much difference within Year levels as between Year levels (spread). Considerable within school variation (suggesting individual teachers make a significant difference to student learning); • The needs of many students, but particularly those ‘at risk’ or ‘left behind’, are not being met. • Differences in performance were largely due to an inadequate understanding of fractions, decimals, and proportion, and a reluctance/inability to explain/justify solutions. © Dianne Siemon 11 10.5 Overall Metro Rural 10 9.5 9 8.5 Year 5 Year 6 Year 7 Year 8 Year 9 Mean Adjusted Logit Scores by Location November 1999 Recognised as multiplicative thinking (Vergnaud, 1983) The views of students: [When did you last enjoy maths?] “In class recently, doing fractions, changing fractions to decimals, it was good because I actually understood it and I felt better” (Matt, Year 6) Success is crucial to engagement. Relevance is about connectedness, not necessarily about immediately applicable, ‘real-world’ tasks, but about being able to access what is seen to translate to further opportunities to study ‘real maths’ and access to ‘good’ jobs. Self-esteem - students believe that mathematics is important and relevant, they generally want to learn and be able to apply mathematics. Mathematics is not perceived to be as ‘boring’ or irrelevant as is often assumed. (MYNRP, Final Report, 2001) © Dianne Siemon “Change the way it’s explained, they need to think about how you understand, not how they explain” (Vincent, Year 9) The most critical element in their learning from the students’ perspective is the quality of teacher explanations, in particular, the capacity of teachers to connect with their level of understanding and communicate effectively. “Don’t understand how it is set out, don’t like to write it down if I don’t understand … idea there, but how to write it, what to do with it ” (Carl, Year 9) Student engagement is related to the individual’s capacity to read, write, speak and listen to mathematical texts (communicative competence), that is, the ability to access the forms of communication used in mathematics. (MYNRP, Final Report, 2001) © Dianne Siemon Notion of targeted teaching that requires: • access to accurate information about what each student knows; • a grounded knowledge of learning trajectories (key steps in the development of big ideas and how to scaffold these); • an expanded repertoire of teaching approaches which accommodate and nurture discourse, help uncover and explore student’s ideas in a constructive way, and ensure all students can participate in and contribute to the enterprise; • sufficient time with students to develop trust and supportive relationships; and • flexibility to spend time with the students who need it most. © Dianne Siemon (MYNRP, Final Report, 2001) MULTIPLICATIVE THINKING A muffin recipe requires 2/3 of a cup of milk. Each recipe makes 12 muffins. How many muffins can be made using 6 cups of milk? Solutions which rely on counting all groups are essentially additive. Solutions which rely on some form of proportional reasoning are essentially multiplicative. © Dianne Siemon The Scaffolding Numeracy in the Middle Years Research Project (SNMY, 2004-2006) • Multiplicative thinking operationalised in terms of (i) core content knowledge (multiplication, division, fractions, decimals, proportion etc), (ii) ability to apply that knowledge in unfamiliar situations, and (iii) capacity to communicate and justify solution strategies • Hypothetical Learning Trajectory (Simon, 1995) for multiplicative thinking derived from the literature • HLT used to locate, design, trial rich assessment tasks • Cluster-based purposeful sample of 3200 Year 4 to 8 students in Victoria and Tasmania, pre/post test design, support for targeted teaching • Item Response Theory specifically Rasch analysis (e.g., Bond & Fox, 2001) used to identify shift over time and test HLT © Dianne Siemon Dianne Siemon, RMIT University Rich Tasks The SNMY tasks were selected or designed to: • assess all aspects of multiplicative thinking as defined • provide opportunities for all students to demonstrate their understanding of multiplicative thinking and their capacity to work multiplicatively; • reflect ‘best assessment practice’, including open-ended tasks, a range of response modes, opportunities for learning; and • be used locally with reliability and confidence. © Dianne Siemon (SNMY, 2004) ADVENTURE CAMP … TASK: a. b. RESPONSE: No response or incorrect or irrelevant statement 0 One or two relatively simple observations based on numbers alone, eg, “Archery was the most popular activity for both Year 5 and Year 7 students”, “More Year 7 students liked the rock wall than Year 5 students” 1 At least one observation which recognises the difference in total numbers, eg, “Although more Year 7s actually chose the ropes course than Year 5, there were less Year 5 students, so it is hard to say” 2 No response 0 Incorrect (No), argument based on numbers alone, eg, “There were 21 Year 7s and only 18 Year 5s” 1 Correct (Yes), but little/no working or explanation to support conclusion 2 Correct (Yes), working and/or explanation indicates that numbers need to be considered in relation to respective totals, eg, “18 out of 75 is more than 21 out of 100”, but no formal use of fractions or percent or further argument to justify conclusion 3 Correct (Yes), working and/or explanation uses comparable fractions or percents to justify conclusion, eg, “For Year 7 it is 21%. For Year 5s, it is 24% because 18/75 = 6/25 = 24/100 = 24%” 4 A Year 6 Student Response to Adventure Camp Short Task (SNMY, May 2004) © Dianne Siemon SCORE Variable Map Relates students scores to item difficulty Items of similar difficulty are grouped together to form Levels or Zones, for example, Zone 3 (SNMY, 2004) © Dianne Siemon Description of what students at each level CAN do Teaching advice to consolidate and establish Teaching advice to introduce and develop The Learning Assessment Framework for Multiplicative From the Learning and Assessment Thinking Framework for Multiplicative Thinking © Dianne Siemon (SNMY, 2006) Zone 4 can be viewed as a transitional zone from additive to multiplicative thinking, suggesting that about 40% of Year 7 and 30% of Year 8 students might be deemed to be ‘left behind’ in terms of curriculum expectations … 100% Zone 8 Zone 7 Zone 6 Zone 5 Zone 4 Zone 3 Zone 2 Zone 1 80% 60% 40% 20% 0% Year 4 Year 5 Year 6 Year 7 Year 8 Table 2 Proportion of Students at each Level of the LAF by Year Level, Initial Phase of SNMY, May 2004 (N=2747) © Dianne Siemon An 8 year range…. LAF Zone 1 2 3 4 5 6 7 8 Expected by End of Year 1 End of Year 2 End of Year 3 End of Year 4 End of Year 5 End of Year 6 End of Year 7 End of Year 8 Year 4 6 6 5 5 2 1 1 0 Year 5 3 5 5 5 2 3 2 0 Year 6 1 2 3 5 4 5 5 1 Year 7 1 2 2 6 3 3 6 1 Year 8 1 1 2 6 4 5 5 2 Table 3 Implied class distribution by Year Level based on SNMY data (2004) – possible groupings © Dianne Siemon 27 Targeted teaching works For example, students in an identified sub-sample of ‘atrisk’ students within the SNMY Project demonstrated major shifts in achievement against the Learning and Assessment Framework for Multiplicative Thinking (LAF) as a result of an 18 week, 2 sessions per week teaching program* (Margarita Breed, PhD study) Participants: 9 Year 6 students identified at Level 1 of the Framework in May 2004 Results: All 9 students achieved at Level 4 or 5 of the Framework in November 2005 * A copy of the Intervention Teaching Program for At Risk Students is included in the SNMY Project Findings, Materials and Resources available on the DEECD and TasEd websites. © Dianne Siemon Recognition that something more is needed Variable success of targeted At-risk student responses to MYNRP interviews (Siemon, Virgona & Corneille, 2001) teaching, particularly in secondary schools (SNMY Final Report, 2006) Role of affect and relationships in effective targeted teaching (Breed, 2011) Over the last several decades, education research in Australia has experienced a number of so-called ‘turns’ – linguistic, cultural, postmodern, spatial and, more recently, … the ‘affective turn’ … The turn to affect is driven by a recognition that the economic rationalism of education is at odds with its emotional and creative dimensions (Kostogriz & Cross, 2012, pp. 389-390) © Dianne Siemon Reaching Them and Teaching Them* Sagor and Cox (2004) have identified five essential feelings they believe are crucial to a young person’s well-being and success at school: • the need to feel competent, • the need to feel they belong, • the need to feel useful, • the need to feel potent, and • the need to feel optimistic” (p.4) This is referred to by the acronym CBUPO. They explain why working on the behaviours and attitudes of discouraged learners alone is insufficient and suggest the inclusion of an additional dimension, that of role. * Sagor, R. & Cox, J. (2004). At-risk students: Reaching them and teaching them. Larchmont, NY: Eye on Education © Dianne Siemon The Reframing Mathematical Futures Project RMITs AMSPP Round 1 project Reframing Mathematical Futures was aimed at improving student outcomes in relation to multiplicative thinking and proportional reasoning in Years 7 to 10. It particularly targeted those students whose future would otherwise be constrained by lack of access to these critical aspects of school mathematics. The SNMY materials were used to deepen teacher knowledge in this domain and improve teacher responsiveness to student learning needs. © Dianne Siemon Approach: The project supported a small group of school-based SNMY specialists in each participating State or Territory to work with at least two Year 7 to 9 teachers of mathematics in their school to identify student learning needs in relation to multiplicative thinking using the SNMY materials. It also supported a Professional Learning Community (PLC) approach that enabled the SNMY Specialists and teachers to design and implement targeted teaching responses that addressed student learning needs in age-appropriate ways that also promoted the five essential feelings. © Dianne Siemon Project partners identified up to 6 schools in each participating State or Territory that were either already investing in numeracy support or where there was a willingness/capacity to provide some time release (preferably a day/week) to support an SNMY specialist. The RMF project provided: • 4 professional learning days for Specialists • Up to 30 days time release per school to support the identification of student learning needs and the work of PLCs (e.g., peer observation, professional development and planning) • regular on-line Collaborate sessions, and • at least 2 visits by project team mentors © Dianne Siemon Dripstone Middle School Rosberry Middle School Sanderson Middle School Batchelor Area School Whyalla HS Victor Harbour HS Valley View HS Roma Mitchell SC Le Fevre HS Murray Bridge HS Millicent HS Naracoorte HS AMSPP Schools 2013-2014 © Dianne Siemon Wynyard HS Parklands HS Ulverstone Hs St Peter Claver College St Theresa’s CC Seton College Unity College St Patrick’s College Preston Girls SC Hampton Park SC North Geelong SC Cranbourne SC Hume Central SC Sheffield School Montrose Bay HS Expectations of Specialists: • Identify participating teachers (two per school), obtain consent from parents where necessary • Administer SNMY Assessment Options (at least one class per participating teacher) • Use time release to support marking and planning • Discuss results with project mentor - meet with teaching team to plan approach and targeted teaching activities, • Regularly meet with teaching team to review progress, locate/adapt resources • Contribute to Collaborate sessions and share observations, resources, ideas and activities • Ask questions, use release time purposefully … © Dianne Siemon Data Collection: Data collected July/August and November 2013 • Complete SNMY data sets from just over 1700 students across Years 7 to 10 • Student surveys (attitudes, perceptions of competence, belonging, usefulness, potency and optimism) • Specialist and Teacher surveys (experience, pedagogical content knowledge, reflections) • Field notes from school visits • Artifacts (resources, photos, posters, planning documents) • Student journals (where available) • Principal report on funding, in-kind support, perceived value of project and future intentions © Dianne Siemon SNMY Assessment Data Complete (i.e., matched) data sets were obtained from 1732 students, with the majority of students in Year 8 Year 7 Year 8 Year 9 Year 10 19% 59% 20% 2% Table 4 Approximate proportion of students by Year Level Data sets separated by order of delivery (25 schools did Option 2 first, 3 did Option 1 first) Students who scored 0 on the second test removed from the matched data set Raw scores translated to LAF Levels, Effect Size adjusted to one year and regression to mean Random error checks conducted to confirm accuracy of data entry © Dianne Siemon In a nutshell … There was an overall improvement in student LAF Levels (based on mean scores converted to LAF Levels) from August to November (see Table 2) Despite some contrary results, the overall achievement of students across 25 schools grew above an adjusted effect size of 0.4 indicating a medium influence beyond what might otherwise be expected (Hattie, 2012) Relative change in LAF Levels Number of Schools Increased by at least one level 14 Stayed the same 9 Declined 2 Total 25 Table 5 Changes in LAF Levels for 25 schools completing Option 2 first © Dianne Siemon The overall improvement in student LAF Levels can be seen in Figure 1 below. Figure 1 Percentage of students at each LAF level, all students, August and November 2013 (n=1532) © Dianne Siemon While overall, the median score (in LAF Levels), remained the same on the August and November tests, the spread was far greater for the November results, which is largely explained by the dramatic growth in some schools (see Figure 2 below) Figure 2 Comparison of median score (in LAF Levels) and spread for all students, August and November 2013 (n=1532) © Dianne Siemon Understanding why… One of the recognised factors impacting student achievement is the level of student engagement in the testing process. In November, schools were asked to rate each student by level of engagement using a scale of 1 (low) to 3 (high). While not all schools provided this data – the results are interesting for those that did. Figure 3 Comparison of achievement by high and low engagement (n=928) © Dianne Siemon Student Surveys There was no discernable difference between the Likert items (statements rated in the basis of 1 (strongly disagree) to 5 (strongly agree) in the August and November 2013 data (effect sizes very small). However, there was some evidence of a shift in student perceptions in relation to the more direct questions concerning the five essential feelings included in the November Student survey (n=931 matched pairs) rated on a scale of 1 (strongly disagree) to 10 (strongly agree) (effect sizes small). Thinking about maths … Aug Nov I feel I belong in maths classes 5.71 6.8 I feel competent 6.62 6.54 I feel useful 5.61 6.54 I feel I have choices in maths 5.79 6.66 I feel optimistic about maths 5.54 6.37 Table 6 Comparison of mean ratings on BCUPO questions, November 2013 (n=928) © Dianne Siemon Student’s perceptions of school mathematics Analysis of the student responses to the two open-ended questions on the August Student Survey: • What aspect of maths do you enjoy the most? • What things about maths do you find most difficult or frustrating? suggests these are consistent with data from the student interviews conducted in the Middle Years Numeracy Research Project (Siemon, Virgona, & Corneille, 2001). That is, students desire and value: • understanding and success, • caring, respectful teachers, • quality explanations, and varied teaching methods. They find algebra, fractions and decimals difficult and they resent being singled out, not receiving assistance when they need it, and off-task, classroom behaviour. © Dianne Siemon Drawing Task Think of a situation when you are learning maths well. Draw it. Then, describe your drawing Responses to this task were requested in both the August and November Surveys. To date, approximately 60% of the August drawings and 30% of the November drawings have been considered but there are some initial trends (see Table 4) Initial Category % Aug % Nov Algorithms or text, no reference to self or others 12 7 No response, unclear/irrelevant, sad/frustrated 23 3 Sitting alone in classroom (neutral/happy expression) 15 17 Teacher and self 12 11 Working with other students 15 24 Teacher primary focus in classroom 13 14 Games, manipulatives, real-world 5 13 Table 4 Major features of student drawings, August (n=994) and November 2013 (n=281) © Dianne Siemon No response, unclear/irrelevant, sad/frustrated Algorithms or text, no reference to self or others Just confused and angry with the noise and the maths © Dianne Siemon Teacher and self Algorithms or text, no reference to self or others A young student is getting frustrated on a maths question, but the teacher can see he/she needs help, so the teacher comes over and helps the stuck child. © Dianne Siemon Noise (or lack of it) appears to be an issue When we work as a group and when it is not quite When it is quiet and everyone is working When I’m at home and it’s quiet. No one is being loud and you can think easier. Peace and quiet. © Dianne Siemon On reflection … Targetted teaching informed by quality assessment works BUT targetted teaching ≠ ability grouping/streaming Targetted teaching requires environments in which all learners feel competent, they belong, are useful contributors, have some potency/agency and are optimistic – This cannot be accomplished in long-term ability groupings or streaming. This proved a challenge for some Specialists and teachers for a range of reasons but particularly the perceived pressure to ‘cover the curriculum’ … Recognition that teachers of mathematics need to acquire much deeper understanding of the underpinning ideas, strategies and representations of school mathematics BUT some genuine light bulb moments as teachers experience the benefits of targeted teaching … © Dianne Siemon REACHING THEM & TEACHING THEM … Adolescent learners: • Experience profound physical, social, emotional and intellectual changes • Increasingly focussed on peer relationships • Becoming more complex, capable thinkers • Have unique and diverse learning needs • More inclined to engage in risk taking behaviour • Tend to respond emotionally • May misunderstand adult communications and reactions DEECD (2006). Understanding Year 9 Students: A theoretical perspective and implications for policy and practice. Melbourne © Dianne Siemon Adolescent learners learn best when they: • • • have high levels of confidence and self-esteem, are strongly motivated to learn, and are able to learn in an environment characterised by ‘high challenge coupled with low threat’ OECD (2002). Understanding the brain: towards a new learning science. Paris: OECD Publications Service © Dianne Siemon What will it take? Whose responsibility? A deep understanding of the ‘big ideas’ in mathematics and the relationships Genuine individual choice between them, and a knowledge of student learning pathways (i.e., researchbased learning trajectories) Opportunities to participate in selfgenerated, purposeful activity Access to tools and resources that identify what students know and provide teaching advice in terms of the ‘big ideas’ and learning trajectories Problem-based, investigative learning Recognise the three Rs: relationships, Personal engagement and relationships, relationships … ownership Five Essential Feelings (Sagor & Cox, 2004) And a commitment to ongoing, collaborative professional learning © Dianne Siemon Sagor and Cox (2004) have identified five essential feelings they believe are crucial to a young person’s well-being and success at school, referred to as CBUPO: • the need to feel competent, • the need to feel they belong, • the need to feel useful, • the need to feel potent, and • the need to feel optimistic” (p.4) Beliefs Attitudes Role They explain why working on the behaviours and attitudes of discouraged learners alone is insufficient and suggest the inclusion of an additional dimension, that of role. * Sagor, R. & Cox, J. (2004). At-risk students: Reaching them and teaching them. Larchmont, NY: Eye on Education © Dianne Siemon 52 Feelings of COMPETENCY Consider: How would you feel about arriving at work every day if you felt you were an incompetent teacher? Learning is the work of students – imagine how they feel coming to school each day if they view themselves as incompetent learners? I: When did you last enjoy maths? S: In class recently, doing fractions, changing fractions to decimals, it was good because I actually understood it and I felt better. (Matt, Year 6, MYNRP, 2001) Success is crucial to engagement. © Dianne Siemon A sense of BELONGING Consider: A peculiar trauma of adolescence is the near universal belief that an ‘in group’ exists and, more importantly, that ‘I don’t belong to it’ … Being denied a feeling of belonging is so significant for adults that we still carry the hurt twenty years later (Sagor and Cox, 2004, p. 5) Is it your job to get students to like you? © Dianne Siemon Feelings of USEFULNESS … our feelings of usefulness will be derived or denied as a direct result of both the quantity and the quality of the interactions we have with others (Sagor & Cox, 2004, p. 129) In a one-room school, the teacher recognised they could not do it all … so established: - small learning communities, cross-age tutoring, peer mentoring, co-teaching, apprenticing; - problem-based, investigative learning, where students plan, organise, monitor and reflect; and - a sense of purpose, self-worth through family and community involvement © Dianne Siemon A sense of PERSONAL POTENCY Ultimately, Glasser tells us that our choices in behaviour are the single most significant way that we have to express our personal power. It is through these choices that we assert who we are and what we want to be known for (Sagor & Cox, 2004, p, 157) Misplaced attribution - Discouraged learners more likely to see themselves as ‘innocent victims’ with little control over circumstances that result in frustration, stress and/or failure © Dianne Siemon OPTIMISM Students who have continuously received feedback on their competence, belonging, usefulness and potency have good reason to be optimistic … [more likely to] defer immediate gratification… Likewise, those students who perceive… that they are failing, that they don’t fit in, and that they are not in control of their lives, will likely develop a pessimistic view of their future. They will conclude, “If the future is so bleak, why defer gratification” (Sagor & Cox, 2004, p. 7) © Dianne Siemon THE CHALLENGE How many of our students can say: I feel successful here I feel like I belong here, people like me I feel needed here I have the power to make things happen here I expect to be a success in the future What will it take to achieve this in your school? © Dianne Siemon