The professor did not have very clear lectures. He jumped around a lot and his examples weren’t structured like exam problems. The midterm also was not like the practice midterm. There was limited practice material to study, specifically for the midterm, however, for the final he did give 3 practice finals. This class did not need a textbook and I did not get it. There were no cheatsheets allowed on tests and only a specific calculator, the Canon LS 100TS. The grading scheme was 30% midterm 70% final or 5% midterm 95% final and there was no homework. Overall, I did not enjoy this class and I had to teach myself most of the material and study a lot.

Other reviews make it seem like Professor Hahn is the worst, but I ended up enjoying his course. He is very straightforward and gets to the point during every lecture, while still managing to be engaging.
The grade is completely made up of the midterm (30%, or 0% if worse than final) and the final (70%, or 100% if better than midterm). Then, there is an additional curve that is based on your rank amongst others in the same class. Both exams were multiple choice, with the midterm being around 30 questions (65 minutes) and the final being around 50 questions (120 minutes). Going through the provided practice exams will help, as you can definitely feel the time crunch during the exams.
One thing I would recommend is to look at the material ahead of time, especially since Professor Hahn posts all of the quarter's material on Canvas during the first week. I found that reading through the typed notes before going to lecture really helped my solidify my understanding and allowed me to actually focus on what the professor was saying, instead of frantically trying to copy down notes during the lecture.
This class can be challenging since the material gets denser as the quarter goes on, but you will succeed if you put in at least a little bit of effort to study and review the material outside of the lecture.

Reading previous reviews of this class gave me a false impression of what to expect. I am actually pretty grateful to have had Professor Hahn for 41. His accent is more than manageable, he clearly knows the material inside and out, and his lectures are straightforward and articulate. He did several reviews of material prior to exams.

Aside from studying, I do think who you get for your TA makes the biggest difference in how you perform. My TA just went over homework problems, which pale in comparison to the complexity of exam problems. I ended up bouncing around and found a few TAs that actually deepened my understanding of the material.

For the people who reviewed and said they were curved down, personally I doubt that. He makes it clear in his syllabus that if your raw scores are within a range, you can't be curved down and will still receive an appropriate grade.

All that being said, this class is hard. Very hard. To do well, you MUST have a thorough understanding of the concepts. As in doing the HW problems over and over won't do anything for you as they only help you get a sense for how the theory is applied in practice. It's a theory class, so some thought needs to be put in to how the mathematic mechanics works. Know why the formulas are the way they are, and how to manipulate and apply them to various problems.

This class was very challenging in regards to the material and mentally. While I received an A, I have never studied harder for an exam. Our grade was made up of a midterm (30%) and a final (70%) or just the final (100%). The class average on the midterm was pretty high (around an 87%) so he made the final harder to bring down the class average. Professor Hahn uses the department curve to grade his class, so essentially you are graded based on how well you do compared to your classmates. He ranks you based on how well you do on the midterm and final and then distributes grades based on the department which is 25% A- and above, 35% B- and above, 15% Cs. I would say that the content is relatively difficult but if you attend lecture and do the homework problems it helps a lot. Hahn is a pretty good professor and I thought he was good at explaining things. This course was just mentally exhausting because of its structure and the whole ranking process. This was probably the hardest premajor class I took for business economics. Make sure you stay on top of the homework and to attend TA sessions because they are very helpful. The midterm and finals were both pretty similar to the practice ones he gave, we were just short on time. The midterm was 30 questions in 1 hour and 10 minutes and the final was 51 questions in 2 hours. Make sure you know the content really well because almost everyone ran out of time on the final.

he's very straight forward and don't spend too much time on theoretical bs. I personally find his exams to be quite challenging but if you practice enough, don't think it is that bad. He doesn't mess around and doesn't tolerate any excuses, he uses lockdown system during the tests so be careful if you are not well prepared. Overall he is still one of the nicest professor at ucla and I would be happy to take his class again in the future.

Professor Hahn is actually not as bad as the reviews say, you can definitely get an A if you put the work in. Econ 41 is not easy and his approach using math actually simplifies it. One thing you need to know is Hahn loves to connect all the materials and put them all into one question, that's why the exam questions are hard. Also you need a strong calculus foundation to be able to work on the exams. Despite all that, his lectures are pretty clear and logical to me, even if you have hard time you can always go to his lecture time or office hours and he will help you out. He even points out what chapters are harder and how you can prepare for them. He also gives practice exam questions to the TAs so having a nice TA is important because some will explain and give more practice exam questions than others (my TA was completely useless so I jumped section which helps). Overall, don't expected easy A from these classes but if you know how A is totally doable.

As indicated by other reviews, Professor Hahn isn't the best professor and often explains things in a far more complicated way than needed (and his messy lecture notes that are almost impossible to read and understand without rewatching the lecture), making this class difficult. That being said, however, he does get the job done and it is still possible to do good in this class. The class was fair and ultimately you get what you put into it. Also, the curve can really help you (top 25% get A/A-, 25%-65% get Bs).

Lectures: His lectures consisted of brief introductions to formulas and then some examples/going over the problem set questions. It was easy to follow along and he explained things well, but not concisely or in the most direct way. There was not much explanation of why/how to use the concepts, just on memorization for the test.

Problem Sets: There were a total of 15 homework assignments that consisted of 7-10 questions and were graded for completion. They weren't too difficult (especially later in the quarter) and both Hahn and the TAs went over them so you know if you're doing them right/wrong. The questions did closely match those on the exams so use these to study.

Exams: Class consisted of one midterm (35% of grade) and one final (60% of grade). The questions were fair and close to the HW questions (with a little bit added difficulty), but there is a BIG TIME CRUNCH on both exams so it can get tricky. Many students couldn't finish Open note due to online but we had to use the responds calculator which added unnecessary stress. Class medians were 62% for midterm, 71% for final.

Clarity: Hahn isn't the most clear and approaches statistical topics from a calculus perspective (so it is different from other stats classes you may have had). His lecture notes are messy but watching the lectures fully will help clear things up. He was good with communication and sending out reminders.

Helpfulness: Besides from the Problem Sets, no other resources were given so you are on your own. He did host live Q&A portions during scheduled class time and they were recorded, but you will have to fend for yourself.

TLDR: This class is made more difficult by Hahn, but its not impossible. Focus on the exams and really understand how the HW questions work and you should do fine.

Overall, he is not a bad professor. I read a lot of bad review on his review. I don't know why, he is a nice guy. Even his exam is really time limited, but everyone does. You don't lose any advantage. He will post lecture almost a week ahead, which is really organized for student to learn new materials. As I said, his exam was tough, because he didn't allow use calculator. If you're good at math, this is a nice class for you; if not, you need consider take this class or not. BTW, His HW is the key to success in the exam.

I'm here with an honest review of Professor Hahn. Just had him for Fall 2020. I got a C.

All of these salty comments are from people who do not understand how elite our school is. My classmates and I faced a grade of the following scale: [HW x 0.05] + [MIDTERM x .35] + [FINAL x .6]. Really hard odds. Examinations are very thorough and you have little time to complete it. He gives you so much material. It's extremely math/stats intensive.

All of this being said, Professor Hahn is actually a really good professor. I find other reviews on him calling him "sleepy" and "un-engaging" and "hard to understand" to be short-sighted slaps to the face from ignorant people. Yes, he has an Asian accent, but his language is still comprehendible. Yes, his lectures sound cumbersome, but what is he supposed to do when teaching such difficult math at the UCLA level? Is he supposed to be jumping out of his chair in excitement every sentence?

To all the people complaining about the way he talks, the legibility of his notes, the unfair grading scale, the TAs, GROW UP. The professor was fine. In fact, he was extremely nice. You're complaining because you don't want to put in the extra effort of studying, attending live lectures, going to office hours and emailing him extra questions. Stop bagging someone just because you didn't want to put in the work. I gave it 100% and only got a C. It's tough. The Economics pre-majors are tough. But if you can't get a passing grade, it's not the professor's fault. It's yours. Classes like this are extremely tough and it's your choice to take this major.

If you are ever planning on taking this class with this guy, prepare to live through hell for 11 weeks of your life. He is THE WORST PROFESSOR EVER PERIOD. Don't be like me and listen to the numerous horrible reviews this guy has. He single-handedly fucked up my entire GPA so be ready for that. I hated taking this class with him. You will too. His lecture notes are incredibly messy and he honestly, genuinely does not give a fuck about his students. If you still want to take his class after reading this, be sure that I'm praying for u.