Worst class I have ever taken at UCLA. Went every lecture at 8am, went to every discussion, did the homework problems and still got a failing grade. I have never felt so dejected in a class. Prof Hahn really expects you to master the concepts that he went through only once. I'd say you can only do well in his class if you put in 3 times the amount of effort you put into an average class. He also speaks quite condescendingly when you ask him about material from the lecture and replies you with yea I went fast because you should have already known and read this before. Lectures were okay but did not explain some concepts well. The exams were a horrendous time crunch and it was all MCQ so you don't get partial credit for work done if you don't arrive at the correct final answer. You don't have time to think, once you read the question you should have the entire solution in your head. I read the reviews on here and thought that it was an exaggeration but the exams are actually horrible. Overall, unless you have a strong background in stats or are willing to put in extra effort, I would not recommend taking ECON 41 with this professor.

DO NOT TAKE CLASS with him unless necessary. Hahn gives really sleepy lectures fueled with unnecessary math. He makes fundamentally easy material hard to understand because he actively refuses to provide any intuitive sense; instead, this person is dane crazy with mathematical formulas while they are often unnecessary to understand the concept.

What makes things worse is the fact that his iPad based lecture notes are completely unintelligible and are lack of any necessary structure (sort of an iPad scratch paper). He writes in HUGE and sloppy fonts (3 lines per page, PER PAGE IN LETTER SIZE ) that are aesthetically disgusting. Anyone who wants to write down nice notes will fall into physiologically unwellness.

The grade is only composed of 1 midterm and a final, and it's a time crunch for most people. He does not allow us to use our own calculators, instead, we can only use the silly calculator provided on the respondus secured testing software (which is extremely hard to use given that it's computer-based, no formatting, and sequence-based (eg. 1+2*3=9 instead of actual 7).

DO NOT take this class with this professor. I feel like I've learned nothing except how to memorize homework problems and take unreasonably timed tests. The medians for the midterm and final were in the 60s for my class, which tells you a lot.

Don't be like me and ignore the advice of the other people who posted reviews. Hahn is genuinely the worst instructor I have ever had for any class. He structures the class so that roughly 15% gets D's and F's, and roughly 5% of the class get's a C-, which also isn't good enough to complete the requirement for the Economics major.

His grading is based on class rank, and the only grade categories are the midterm and the final, meaning that your final grade in the class is dependent on roughly 90 multiple-choice problems (30 problems on the midterm, 60 problems on the final). This can be especially awful because of the fact that since most people can't actually finish the exams in time, a lot of the final scores in the class are based on how well you can guess on the last few problems (which have a significant effect on your final grade, since there are only 90 problems for the entire class).

His exams are extremely time-based, meaning that simply understanding the material well isn't enough. You need to have hammered all of the problems into your memory because of the time-constrained nature of the exams. He even cut the final exam one hour short because he didn't want to give us too much time (from 3 hours to 2 hours). This means you get roughly 3 minutes per problem on the midterm, and roughly 2 minutes per problem on the final.

I would recommend doing every homework problem (even the ones he doesn't list) and constantly reviewing practice problems. He doesn't collect homework, but it's very good practice.

Going to lecture helps, but everything he writes down in lecture is from a piece of paper that he prints out that he also posts online at the beginning of the quarter. You don't need to go to lecture, but discussion is very important to make sure you understand the concepts well in the homework.

For my class, the class average was a final grade of B-, with an average exam grade of roughly 60%.

The grading system is as follows:
Midterm: 40%
Final: 60%

He doesn't let you replace your grade on the midterm with the final, so much of your grade will be set in stone by the time you take your midterm in week 4. This ends up putting too much pressure on one single exam, and if you aren't used to/prepared for the time-pressured nature of his exams, you're going to suffer immensely. Don't mess up like me by taking Hahn. Take literally anybody else. My friends took Sheng the quarter after, and though people didn't like her teaching style, she was much more fair and people typically did better.

Important note: I took this class during the pandemic, so it was completely online. During a normal quarter it would likely have been very different.

Professor Hahn is unclear in his lectures. The material is made unnecessarily difficult with the addition of confusing math concepts that you do not have to know for exams. The two exams (midterm worth 35% with ~30 multiple choice questions, final worth 60% with ~60 multiple choice questions) are difficult and very rushed, as you have approximately 2 minutes per question and no calculator except the terrible built-in Respondus calculator. The last 5% of your grade is based on completion of the 15 homework assignments, which are overall doable but with some difficult problems. The exam questions are usually more challenging than the homework and are very different from those problems for the most part, making it hard to study effectively because there is little practice outside of the homework. The only saving grace was that we were allowed to use a cheat sheet on exams, but because of the fact that the exams were rushed you can't spend a lot of time trying to find the matching concept. The textbook is not helpful at all and I would recommend not purchasing it.

I took Stats 10 the quarter before taking this class, and it was somewhat helpful because some concepts were more familiar, but taking it doesn't mean the class will be easy. If you can, try to avoid taking this professor, but if you can't, then it is possible to do well if you put the work in.

DO NOT TAKE ECON 41 With Hahn. The professor does not provide any sort of practice exams, nor does he prepare you for the exam in any sort of way, which is extra disgusting considering that your grade consists of only the two midterms and finals. The wording on the homework questions he assigns is completely different from the wording of the test questions. His teaching methods and exams make Econ 41, a class with easy materials, way harder than it has to be. The only thing you have to work with is his lecture notes, which is a complete mess and hard to read, and the homework questions. Do yourself a favor and take this class with another professor.

Professor Hahn is not that bad. His class may not be clear enough, but his notes and homework are very helpful. Econ 41 contains easy materials, but Professor Hahn made his exams extremely difficult. If you want an A in this class, I suggest you take Stats 10 first or at the same time (the easier version of Econ 41). His calculation amount in his exams is far beyond my imagination. No cheat sheet this year, so you need to remember everything. Be prepared and good luck :)

Please do not my mistake and ignore the terrible reviews for Hahn on here.

Here is what I submitted as Professor Hahn's performance review... I stand by every word here.

"Jinyong Hahn is without a doubt the worst professor I have had at UCLA so far. Professor Hahn, if you are reading this, you are the absolute worst. I have never dreaded going to a class as much as I dread your class, you ruin my mornings and always seem so unpleasant to be around. Professor Hahn had maybe the most ridiculous grading structure of all time for this course. To start out, students are up against a pure curve with 13% of the class getting D's or F's, and 22% of the class receiving a grade of C- or lower (which qualifies as not passing according to Business Economics and Economics pre-major requirement). How can he be failing a fourth of his students who all need this class to pursue their major???? And if this is not harsh enough, he structures his grading system so that you can drop your lowest midterm score. This is not a new concept, and typically works out fine in classes. However, when a "veteran" teacher like Hahn designs his tests so that the median of the first midterm is a 92% and the median of the second midterm is a 60%, the students who did not preform as well on the first midterm are driven into their Econ 41 graves without a hope to come back from their poor performance.

Overall, I think that Jinyong Hahn is a smart guy, but a terrible professor and (not that it matters for his job) a pretty lame person. Whether or not whoever is reading this actually cares is a different matter, but writing it made me feel a little bit better as I'm desperately studying for Hahn's final to salvage my hopes at a Business Economics major. Jinyong Hahn could be teaching the cure for cancer or the true nature of the universe and it would still be dry and make me wish I chose to come to a different university. I thought I liked statistics, but thats far from the truth after this class. All around terrible experience in Mr. Hahn's class. "

Hahn is one of those professors some students really like and some students really despise. His tests are very time-pressured (about 46 questions in 60 minutes) to the point that the best way to study for his exams is to grind the course material into your brain till it becomes second nature. He allows the use of a cheat sheet on exams, but many students will not have time to search for answers on their cheat sheets since time is so limited.

Hahn can sometimes come off as condescending when he is explaining material in class and implies that the statistics we learned in previous classes was useless. He is super strict on his grading policy and almost flat out rude about the way he explains his grading policy. Your grade is based purely on your performance relative to the class, and the ratio is 40-60 between the midterm and the final.

He might seems to be strict at first, but he is very nice indeed. He is very patient to answer your questions and help you on concepts.

One problem is that sometimes he seems to use a more confusing way to explain a concept again. Maybe that method works for others, but not for me. But no need to worry about it, at least you can understand one of the method he expained. His exams are not easy, but the grades are strictyly curved. I like it. I get less than 90% in the midterm and final, and end up with an A+

Take his class if you like super nice and knowledgable but not-that-effective teachers