I want to make students feel safe to participate, safe to ask questions and safe to answer my questions. A defensive brain cannot learn, only a brain at ease can build up new connections. Making students feel safe is all about how the teacher acts and reacts when interacting with students. Thus, I would agree tha teaching is a performance art.

My students are easily intimidated: the subjects I teach are difficult, and notoriously so. I am a big person, endowed with significant authority and power by the university for which I teach (when I teach by myself, from the students point of view, I can decide over pass and fail for every student, certainly I can adjust the difficulty of the exam). Knowing this I used to keep myself from being too open, from appearing aggressive, from letting my enthusiasm and my feelings express themselves. However, over time I realized (and read in many places) that exactly this show of enthusiasm is what will motivate the students, make them feel interested and even safe. I guess it is generally possible to be overly enthusiastic, to be too aggressive; this would probably have to be controlled. However, I'm naturally not a person who expresses his feelings strongly, so I never had any problems with it: since I started letting my enthusiasm out into my teaching, into my interactions with students, they seem to be more motivated; more importantly, though, I'm more confidents. I trust in myself and in my fire for the subject I teach, and from that source I take the drive to teach as good as I can.

Enthusiasm (and showing it) is at the core of a good atmosphere. I use a number of further approaches and best practices to improve it further.

• The first and most obious thing is to not be condescending. Note that this is not the same as praising all students for all comments. I routinely tell students when they are mistaken, the key is to do this in a respectful and, in particular and imperatively,

  appreciative way. When a question leads too far astray I just say that I am open to discuss this after class and that I want to stay focused on the topic (even the students asking such questions appreciate me focusing the discussion). When an answer might be correct, just not what I want to focus on right now, I tell the students something like "This could probably also work, I'm not sure; for now I want to focus on a different way of answering this question". Overall, giving honest feedback to students has served me well; what's important is that I truly consider the statements of the students, taking my time thinking about them before possibly dismissing them.

• The students feel naturally a distance between me and themselves: I'm older, tall, I easily handle the material. Also, I'm endowed by the university with significant power (I decide who fails, definitely I design the final examination). Whenever I'm teaching alone (or at least as the only senior teaching staff), the students have basically no one else to turn to (if I'm teaching in a team, this is somewhat relaxed). I'm trying to reduce this distance as much as I can. First, I address students by their first name, and make sure they address me with my first name; this gets me closer to their level, teaching them more like a peer with insight than like an authority which needs to be followed.
• I want the students to feel comfortable participating. Once students regularly see others participate and also participating themselves, further participation comes easily. So the question is how to get this initial participation. I do this by raising the threshold for participation slowly: I start with questions like "Who of you is in the first semester?" or "Who studies computer science?" (depending on what discriminates between different students in the class). I frequently ask simple questions about the content and only occasionally harder ones. In my own studies, lecturers tended to glance over more easy parts and only turned to the audience with more tricky questions (frequently not even suitable for the good students); this demotivates students and makes participation tiresome. I try to have a good mix of difficulties, giving everyone the chance to participate.
• I have seen many lectures that focus on the best students: only the top performers in the class can truly follow, for more than half, frequently many more, the task is to copy the wisdom from the black board to the note book and try to make sense of it later. (I am wondering whether students really make sense of it later, or just try to read through it when solving problems?) My teaching mostly (tries to) ignore the top 10 percent or so of a class, and to direct the attention to the next 60 percent. This way the time spent together benefits a lot more people than it otherwise would. A class only for the top students makes everyone else feel bad and eventually uninterested, while the top students can easily handly a class that is "too easy" (for example by not going to class, which is a fair way of dealing with a class that's too easy).

First impressions are crucial, so the first lecture is very important for the success of a lecture. I like to spend at least half of the first lecture on getting to know one another and about setting the tone and atmosphere of the lecture. I typically start with presenting myself (and whoever else participates in teaching, such as tutors), followed by some general questions to the audience (first give something of yourself before asking something of others). This also helps the students getting to know one another. What I'm trying to learn about the students:

• What is their background? What program do they study? For how long have they been at university?
• How is their knowledge in some required prerequisites?
• What do they expect from this class?
• What motivates them taking this class?

• Asking questions to be answered by raising hands (or by clicker). Suitable for very large audiences, but also smaller groups.
• Let students sort themselves regarding some criterion along a wall (for example by first name, or by distance of place of birth to the lecture hall). Not so suitable for very large audiences, and requires rather more than 10 students.
• "Key to me": Everybody, starting with myself, goes through their key chain and explains what each key is for. Suitable for small audiences (<10 students)
• "Flashlight": Everybody, starting with myself, says two sentences about something related with the course ("What do you expect from this course?"). Suitable for medium and smaller audiences (<50 students).
• Anonymous and spontaneous test. Not popular, but ok since it's anonymous. It's great for ascertaining ability.

There is one more important thing happening in the first class: I'm presenting the way I'm teaching, also on a very abstract level. I'm trying to make the students understand why I teach the way I teach. I might be talking about using clickers and why this helps them understand the material. I'm telling them that my course is going to be different from what they are used to, and I encourage them to give this different way a chance: I believe that the learning outcomes are better, that the learning is deeper and the insights won't be forgotten after the exam, but will help them through their professional life. I find the students much more accepting of my (sometimes a bit strange) experimental teaching if I let them know why I teach the way. What they don't really like is to feel like a guinea pig - I had more success with telling the students that my teaching is different and thus more successful, than with honestly admitting that I'm trying a lot of new things (both are true statements, basically in any of my courses, though I never stray very far from known ground - after all, I should not mess up the students in my class completely).

I've found Eric Mazur's pitch for how much a waste of everyones time classical lectures are very convincing. It's summarized by the German bon mot "Alles schläft, nur einer spricht, das nennt man Hochschulunterricht!" ("everybody sleeps, only one person is talking, that's called university teaching"). In my own studies, it was mostly accepted that we students spend the lecture time copying from the black board, not thinking. Given that the notes might as well be copied and distributed by the lecturer, this is really a ridiculous waste of time. At some point I startet only taking notes about the main points, that helped me be able to actually follow (and make use of the lecturers spoken words - in fact, why do they talk anyway? Most people cannot really keep up with copying down the material, so the spoken words are just to mask the silence, I guess). These days, in computer science, we lecturers are somewhat expected to use slides and make them available to the students. Thus, the students could focus on spoken words (sometimes even making sense of them, possibly taking notes not about the details of what was said, but about the ideas conveyed).

In my experience, this practice begets a new problem: the students now have to follow a 90 minutes monologue. This is very tiring even for the best of lecturers and by the most focused students. I sometimes read or hear the advice that one should add a break in the middle of the monologue, which sounds like the best way to ignore the actual problem: students cannot focus on material that is ill-motivated and not delivered in the speed they would need. In my opinion, the key to resolve this problem is what is commonly called "activation of students". That's an umbrella term that can mean a lot of stuff, aimed at different situations for various effects. The important aspect is that students are asked to use their brain (like, in the classroom, during lecture time). This can only be done by also recognizing the results of their thinking (else they wouldn't do it). In other words, with "activation of students" there is a shift of agency from the lecturer to the students, from lecturer-centered teaching ("I am speaking knowledge") to student-centered teaching ("You are making connections"), from lecturer-teaches to student-learns. This is mostly considered heretical stuff, since it shakes the foundation of the long-standing agreement between lecturers and students: the lecturer gets to hear his own voice and can be in the center of the stage, and the students are being left alone and don't have to participate.

There are many ways to activate students, I tried peer-instruction (which Eric Mazur can explain to you better than I can) and generally liked it for large audiences (>40 students). For less students I like to have a conversation with the audience (ask questions, including simple ones, giving them time to think) - I guess I do like to be center stage as well. The best way, however, is probably any kind of problem-based or research-oriented teaching (i.e. the teaching that we use for PhD-students, or in any kind of project courses).

As lecturer I am given two roles: teacher and examiner. In my experience they are very much conflicting, and not just when my students ask me whether certain material will be expected in the final. I try to separate the two roles over time: first I teach as best as I can with the students best learning at heart. Once the teaching period is over I test as objectively as I can, with my role as an examiner as my driving motivation. I sometimes think that it would make more sense to completely separate these two roles, so that two different persons would teach and test.

Teaching is something that so far does not, as a rule, happen in teams. Sure, I might have some tutors to take care of the tutorials, or I might ask a fellow lecturer about how he would do it. But in the end I get to decide what and I want to teach, and how. I find this rather strange: a lot of things are done more and more in teams, there is even coding with two programmers in front of the same computer, yet close to nobody seems to think about truly teaching in a team. I think the reason is mostly economic: it's cheaper. Teachers are rather well-paid, and the demand is huge. What if every university would decide that all courses be taught by two people working together? Sure, this would not double the load, since there can be sharing of a lot of responsibilities, but if it is to make any difference (and not just result in one teaching being resposible for one half and the other for the other half), there will be an overhead incurred. The two teachers need to agree and make compromise: this is the greatest benefit, and it's the greatest cost.

I am collaboratively teaching one course repeatedly, once a year. I'd claim that it's the best course in my portfolio, precisely because I'm not teaching it by myself. Two people can both give their strength, while letting their weaknesses be mitigated by the co-teacher. Working in a team, for me, is also much more rewarding and inspiring, leading to better outcomes. Cruicial for the success is, in my opinion, that all teachers in the team share their passion, and have a way of working together, dealing with conflicts constructively. I guess that's the same for all teams everywhere, not just in teaching.

Not only are lecturers never taught how to lecture, but they are also never evaluated or held responsible for their teaching. You might think that there are student evaluations, which there are, but these can only inform about the quality of teaching a tiny bit (it's a bit like checking a person's temperature: sure, at >40°C something is wrong, but not everyone with 38°C is healthy enough to not care any further). This has, of course, everything to do with the (very) low value that teaching has amongst university lecturers: it's a nuisance, a distraction from research, at best a way to find some students interested in joining one's research group, preferably smart students (they are easily found, since only smart students learn by themselves and don't rely on good teaching, so only they will get a good grade).

Note that the situation is very different in some other countries where teaching staff is judged according to student evaluations, sometimes this is a very central measurement of teaching quality. However, there are several organizations cautining agains such use of student evaluations.

Why don't we have regular assessment of teaching quality? By external professionals? In a constructive way, helping the lecturers to improve, making our teaching better each time we teach? Why aren't younger lecturers taken under the wing of more experienced lecturers? Why is there no culture of exchanging ideas on how to teach (effectively, or, maybe that's also very interesting, efficiently)? What I do is to critically examin my teaching outcomes after each course and with the help of a course outsider. It only helps so much, but at least it helps a little.

For this I do also consider student evaluations, at least they show what was noticable even to students (and also a lot of other items that I don't care for, I should make a hit list of the most ridiculous comments I got). I also take into account student ability in final exams (this shows what they actually learned, and if a lot of them fail, then I failed in teaching them). Most valuable for me is the following feedback loop: for each of my courses I have a course outsider make a mid term evaluation by coming to my lecture. I leave the room while this person spends 45 minutes discussing "What is already good and should stay as is?", "What can be improved?" and "How could these improvements be brought about?" The results are very insightful and help me a lot adjusting my teaching and evaluating new tricks I tried.

Students differ in many respects, and it would make for very good teaching indeed if one took the specifics of students into account. This is probably one of the main reasons why (a) small courses make for better learning and (b) why learning is still done with a lecturer specifically designing the course (rather than just meeting in tutorials and learning from a book). When I teach a large course I try to address differences at least a little, though this seems to be still one of the hardest things for me to achieve. For now I mostly focus on differences in ability to handle the material, though there are many more differences one could focus on (interests, prior knowledge, study program...).

The ability of students probably follows a normal distribution. This means that if my core focus during a lecture is on the top end, I benefit only a small group of people. Thus I decided to focus my teaching more on the middle region of abilities, with asides for top students. The main potential for differentiation lies in the time students spend at home. Here they can progress according to their own speed, look up whatever they do not remember (possibly from previous courses) and also work on different assignments. I leave it to the students to decide what assignments to work on, but I try to give clear indication what the different assignments are good for (they are afraid of missing out, so I have to make clear how they can chose assignments without missing out on relevant material). For top students (typically only the top 10% of the class) I have bonus material. Here the students get additional material and a tough question. As a motivation I give bonus points: one bonus point per assignment, for a total of 10 bonus points, each point being a bonus point for the final exam (which is worth 100 points in total, not counting bonus points).

One key difference between different students is how well they can manage themselves (their motivation for the course and their needs for exercise). Typical students have some problems in this area, so I make a certain amount of exercise mandatory. For good students (working on bonus material) I somewhat waive this restriction: each bonus assignment not only gives bonus points, but also regular assignment points, effectively making it unnecessary to also work on regular assignments. Student copying solutions from others (or just slacking off while the team mate solves the exercises) effectively bypass my attempt at helping them with their self-management. I typically let this happen -- it is difficult and annoying to try to prevent it, and the students hurt mostly themselves with this strategy.

Giving students the choice of which assigments to work on has another positive side effect: as research on psychology has shown, just being able to make a choice makes people happier with this choice (rationalizing the choice as a good choice). This is particularly strong when the choices are more significantly different. For example, I like to give students a project to work on, extending the material of the course. They can chose between a number of different projects, thus giving them the ability to choose a project according to their interests (and possibly ability). I believe this is also a key reason why seminars, where students can pick their own topics, are more motivating. This seems to me also to be a key reason why elective courses are more popular than mandatory courses, and why students are more motivated by thesis work (which is typically a tailored topic for them).

According to ECTS-regulations, for a 6 ECTS points course, a student is supposed to work for 180 hours. Counting two meetings per week of two hours, for 15 weeks, we only have 60 hours of time being present at the university. If we assign 20 hours for exam preparation, then we are left with 100 hours for a semester of home work. If I give 10 exercise sheets in a semester, I can thus expect students to work for 10 hours on each exercise sheet. (Note that this computation is difficult for various reasons: (a) not all students are the same, some might take longer for the material, others shorter (b) a load of 30 ECTS in a semester of 15 weeks thus expects the students to work 60 hours per week -- on average). I have no solution to these problems, though it seems to me that lecture-free time is frequently free of university obligations, at least for computer science related disciplines (some others are very different, with major assignments in lecture free time). Making some courses (for example for soft skills) block courses in the lecture free time could thus make some room for lectures during lecture time.

I cannot change the system of the university, but I can design my own course. The key question is now how to make use of the learning time that the students have at home. I agree with the observation of the flipped classroom teaching concept that lecture time would be wasted just giving students new material (to copy from the board and to read and try to understand at home). Thus, I give students material (basic definitions, simple concepts, examples for clarification...) as home work. I also give some simple exercise about this material (this (a) makes sure the students consume the material and (b) helps them understand the material by making them think about it with a concrete question). This frees up lecture time a lot, which I can now use to focus a bit more on helping the students understand the material more deeply.

In the next step, after the students had some guidance and maybe clarification of questions during class time, students are now ready to work on more in-depth assigments at home. I believe that these three steps are a good set up: preparation at home, deepening in class, complex assignment at home. This is typically followed by an evaluation, feedback and possibly discussion by a tutor, which gives valuable advice to the students. I think that, optimally, the students would reconsider the assignment after this feedback and make an even better version (this is what I do with thesis students, naturally), I believe that the learning obtained from that would be even deeper since it reinforces the feedback. However, so far, I have not found a good way to organize this multi-stage process for lectures with home work assigments (other than requiring writing nice proofs over and again).

When I design a new course, I do not start with the specific content ("what do I want to teach?") but with the learning goals ("what should the student learn?"). For learning goals I like to stick to Bloom's taxonomy as a guideline (it's not that I could assign each learning goal an unambiguous level in Bloom's taxonomy, but it really helps thinking about it). I also like to shoot for higher goals than something in a very specific area - if the goal is not useful other than for being able to write a thesis in this area, then the goal is probably not an important goal. For example, one of my main goal for basically all of my courses is "abstract thinking", which I believe students really train in my courses. Also important are "communication skills", in my case precise communication about deductive arguments with a reader in mind, but the skills learned in my classes should also help with oral communication and presentation skills, I believe.

A popular complaint when designing courses seems to be that "there is too little time for too much material". I read two books on the topic of "content reduction" and found both mostly useless. My main insight from these books was that there is no such thing as "content reduction", but rather one has to choose content which best helps achieve the learning goals. A goal like "ability to analyze and design algorithms" one can teach with many different concrete algorithms, also a paradigm like "divide and conquer" allows for many different concrete approaches, but it is not necessary to teach a lot of different instances for each paradigm. What I did take away from the mentioned books: "do a few parts in depth, others only superficially". This means that the students get one example done properly with plenty of time to understand. Other examples are then just mentioned. This can, for example, fulfill both the goals "is able to design a Divide&Conquer algorithm" and "knows the following list of Divide&Conquer algorithms" while not requiring too much time.

I teach classes of various sizes: there are about 80 students in a mandatory undergrad lecture, popular grad level lectures with 10-15 students, specialized lectures with 3-6 students. Also, some popular seminars have about 20 participants, less popular grad level seminars have 3-6 students. These very different sizes of the classes call for very different approaches to teaching. For a lecture with 3 students I have all class meetings in my office, making for a very intimate atmosphere. I know all students not just by name but I also know their abilities. Students have a large influence on the choice of class material (if they want to) and I tailor the class material to their needs. With 15 students I still know everyone by name and try to have some good group dynamics where we can get some kind of a discussion going, but we cannot do proofs together any more. We might break up into smaller groups from time to time, but generally I like to have a discussion with the students, and this still works at this size. This is very different from classes with 80 students. Individual contributions of students are minimal, I use technology such as audience response systems to keep this large a group activated. I need tutors to address students more individually, increasing the distance between me and the students (it's difficult for tutors to forward their insight about student problems to the lecturer - lectures where I grade personally give me a lot of insight into students needs).

Finally, teaching one on one is not particularly efficient, but certainly effective. This is the situation for thesis students, and I enjoy this setting a lot. One can give very individual feedback, correct mistakes accurately and set a focus appropriate for the particular student.

I feel that students are distracted from learning by grades. They derive a lot of anxiety from trying to secure the best possible grade (which is understandable, of course, just not particularly helpful). Rather than trying to focusing on learning, they want to know what exactly will be expected of them for getting a good final grade. I understand current grade inflation as one way to combat this: if everyone gets the best possible grade, then effectively no one gets any relevant grade. This of course makes it impossible to use grades to differentiate between students, for example in order to decide which students to consider for PhD positions. Also, grades provide valuable feedback for students, giving them a sense of their strengths and weaknesses.

Maybe we give too many final grades in a study program. Feedback is good, but it shouldn't be overburdened with so much meaning. I could imagine that students regularly take a proficiency test for programming, for example, constantly improving by taking relevant courses. A final proficiency grade at the end of the studies will be awarded, much like a proficiency level in speaking a certain language. Programming skill is of course not the only learning goal in a computer science degree, so there would be multiple such proficiency levels (for example also one for the ability to write good proofs). Furthermore, there might be a lot of topics which might be "ticked off": the student knows the working principles of compilers, operating systems, databases, algorithm design paradigms and so on. These items do not get a grade, but are basically just a list of items stating that a certain student has a well-rounded knowledge of the subject area. This way, only a few informative grades would be accumulated at the end of the studies, and no course would get an irrevocable grade. I guess this cannot be implemented easily in our system of accreditation, but for me thoughts like these help me reason about grades and grading.

Students with a blue mind set like rules. They like things to go as they should go and for things to be as they are meant to be. The opportunity here is that they trust lecturers immediately and follow the instructions given, which means that lecturers can help them learn easily. On the down side, new teaching techniques might be frowned upon and the lecturer is seen as responsible for learning outcomes (as in a Nürnberger Trichter); effort is expected to be rewarded (by good grades).

Probably the most common color among my students. They want to achieve, they want good grades, they want to perform. For this they expect to be told exactly what the requirements are and what is expected for a good grade (transparency). Learning is not so much an intrinsic value, good grades are. The opportunity here is that points can guide them to do taks that are good for their learning, a transparent and consistent grading scheme makes them align learning with achieving (see also constructive alignment). A big down side is that softer learning goals with harder to quantify quality measures are hard to teach; students might even get upset about unclear learning goals.

Green wants to have a community, wants to learn with others, wants project work. The exercises should be fun and give a spirit of community. On the plus side, learning can be easy and very much intrinsic if the exercises are phrased in a fun way. On the minus side, just being a good sport is expected to be rewarded, having fun seems to be the objective.

Yellow does not really need to be taught, they want to decide for themselves what to do. Any restrictions and constraints are a nuisance that just need to be dealt with. They go to class if it helps them and otherwise find other ways to achieve their goals. They enjoy project work where they can express themselves, have an impact, be meaningful. Yellow students need to be inspired, and then learn with strong intrinsic motivation. They might have trouble getting through a course teaching boring basics with no apparent use.

I've read an interesting article on how to give feedback on homework. The main point I also saw in practice is that students seem to not take written feedback so much into account - they mostly check for the final grading points and are more or less happy about what they see. I find it much more constructive to take the time, for example at the beginning of each tutorial session when handing back exercises, to indicate some problems I see with their work and where they can improve (a variant of what is suggested in the above article).

Overall, I prefer to grade tough and consider all learning objectives that I have (for example, a bad write-up will incur point reductions, since learning how to write good proofs is part of the learning objectives). Being tough (but fair) means that students get feedback that accurately shows them their strengths and weaknesses, rather than highlighting only one of the two parts (the main problem typically being too nice and thus obfuscating weaknesses).

A number of people seem to believe that tutorial sessions are meant to give the correct answers to all homework questions. I believe that this is, mostly, a waste of time. Answers to questions that everybody got right don't need to be discussed. Hard material only interesting to a few is also not important. On the other hand, discussing material already discussed during lecture time might be a good use of time, if the students seem to still struggle with some of these questions. What I like to do is ask students about what they want to discuss, collecting suggestions and then voting on what to do first. If I don't make it through the complete list, that's ok, the bottom of the list is probably not so important anyway.

I might also prepare additional material to work on in small groups during the tutorial. This can serve as additional exercise and might also give the opportunity to focus on a few critical points that should be discussed and clarified somehow.

The students are mostly admitted to the university and told that they have to start with these few courses. Then they go to these courses, each of them basically expecting the students to be able to handle normal-type lectures. The structure of semesters and courses basically doesn't allow for much else. Changing the first semester to make for a smoother transition would probably be a good idea.

Many have bitched about the Bachelor/Master setting, let me just add one point: I sometimes teach courses only requiring some basic knowledge in something or other, which might be of interest to students late in their Bachelor program or Master students. Then it seems to me an absolutely strange setting that all courses have to be either Bachelor courses or Master courses. In the US they have a standard way out of this (basically co-listing the course in both programs) which somewhat works here as well, but here it's a shady workaround.

Another point that regularly annoys me is that I don't know before the first or even second class how many students I'm going to have: how am I supposed to design a class if I do not know how many students I have to teach? Once I had to spontaneously find a larger room, students were sitting on the window sill and on the ground.

What really confuses me about some professors is that they seem to show no humility in the face of being an amateur at teaching. They have gained tremendous scientific insights and are rightfully professors, and their good feeling for their subject is very valuable for teaching students cutting-edge technology - but it is not the only requirement for being able to teach, didactics being another.

I also don't understand why teaching is considered such an unimportant part of being a professor. In Germany, teaching and research are supposed to go hand in hand (so that student can benefit from state-of-the-art knowledge and professors can stay in touch with some of the basics of their profession, while at the same time training and scouting the next generation of researchers). Professors are hired explicitly for teaching; how come that they are allowed to almost completely neglect this part, if they choose to? Why is the general culture such that this behavior is acceptable, including by students?

Who wouldn't complain about the young, the new generation? I'm certainly no exception here, there are plenty of things to complain about. But then I also believe that we as lecturers (together with parents and teachers at earlier points in their life) shaped this new generation significantly. So my question is "What did we do wrong?"

Students focus too much on grades - not surprisingly, good grades is what got them into university. It will be what's getting them a good job. They show not as much interest in learning for it's own sake - I'm again not surprised, many professors show not much interest in teaching.

Also, I'm sometimes wondering why students seem to not be able to tell the difference between good and bad teaching. They rely mostly (I think) on gut feel, heavily influenced by how easy or quick to solve the homework was and how the final exam goes. My evaluations regularly give a better grade for "I have learned a lot in this class" than the overall grade - what exactly, then, is the purpose of the class, if not to learn a lot?

As already mentioned in the rants about professors, why don't students think more about quality teaching and hold professors accountable? Why are they happy to go along with bad teaching, so long as the final exam is easy?