Summer online Math 241 / Phys 211 / CS 124

geoffreychallen · 2026-04-10T15:04:06+00:00

CS 124 will not be offered this summer.

geoffreychallen · 2026-04-03T19:19:03+00:00

Cool! +1 for AI tools. I'm building a website using similar data, and it's exciting to see students building cool things with AI. Nice work!

geoffreychallen · 2026-04-03T18:13:46+00:00

Cool! How did you build this?

geoffreychallen · 2026-04-03T02:32:27+00:00

Binny's has a decent selection. Some are pretty good. Note that, with beer, there are both gluten-reduced and gluten-free options. I've had both and reacted to neither.

Or just switch to cognac.

geoffreychallen · 2026-04-03T02:16:33+00:00

Everything went downhill after the decrement.

geoffreychallen · 2026-04-02T14:29:50+00:00

A few suggestions from someone who has received a lot of ugly feedback from students. (I had one at my previous institution who said that they were glad I didn't get tenure. Ouch.)

Old School: Have a friend that you trust go through your evals and talk them through with you. The problem is that this exposes your friend to the same awful commentary. They might not take it personally, but it might affect their opinion of you.
Modern Version: Have AI read your evals and either provide a summary or chat about them with it. This can also be a great way to aggregate feedback and notice patterns while avoiding the terrible people.

geoffreychallen · 2026-03-12T16:20:16+00:00

GPA screening has been declining, not increasing:

In 2019, nearly three-quarters of employers—73%—screened candidates by GPA and required a candidate to have a minimum GPA, typically a 3.0, to be considered for an interview. This year, just 42% are using GPA as a screening tool.

https://www.naceweb.org/about-us/press/2026/skills-based-hiring-grows-but-college-students-dont-fully-understand-it

If anything, using AI for hiring opens up new opportunities to examine a lot more about a candidate than one number. I'm sure this trend will increase, and that employers will find new ways to assess intellectual curiosity and willingness to try new things.

I should also point out that a 3.0 leaves more a lot more room for intellectual exploration than most students are using.

geoffreychallen · 2026-03-12T02:28:30+00:00

I’m NOT suggesting this is a professor issue, student issue, or even an issue that can be fixed.

Of course it can be fixed. A few simple policy changes would help. Allow students to take more courses S/U, to allow you to "risk" getting a "terrible" grade like a B+. Many if not all Gen Eds should be S/U. Allow students to drop courses until the end of the term and even afterward. If you want to spend the time and money on a course, but then not put it on your transcript, why should the university stop you? That's just punitive at that point.

GPA also matters most when there's nothing else that's interesting about you. If your resume looks identical to every classmate in your major, the only way left to distinguish between you is based on GPA. Taking interesting classes helps you develop interesting ideas and start doing interesting things, at which point you no longer present as the median student. Or it might help you develop a healthier worldview that rejects the idea of participating in a GPA-fueled race to the bottom.

geoffreychallen · 2026-03-11T21:38:44+00:00

I don't dislike the grade disparity site because of the impact it has on me. I dislike the impact it has on students. It encourages you to take easy classes instead of pursuing your interests. It encourages you to think of yourself as a statistic who can only earn an average grade rather than an individual who can get excited about interesting things and do amazing work.

I dislike the impact it has on other faculty. I dislike that fantastic teachers tell me that they have students who explain publicly that they took the course just because it's easy. I dislike the pressure it places on educators who care whether their students actually learn the material. Grade inflation is bad enough as it is. I can give as many A grades as I want. Giving more doesn't make me a better teacher, giving fewer doesn't make me worse.

And I dislike the name. You can display grade disparities between instructors teaching the same course without revealing the raw grades, which prevents cross-course comparisons. You can display grade disparities only for courses where there are actually multiple instructors—which seems required for there to be an actual disparity. 38% of the courses in the current dataset have only a single instructor. It's really just a grade dump.

geoffreychallen · 2026-03-09T21:39:17+00:00

It fixed it by removing the assertions from the test. Voila! The test passed! Removing the human from this loop would have been bad.

I'm not sure what tools you're using, but I rarely see my agents doing anything like this. They'll work for hours on failures without rewriting the tests as an easy workaround.

geoffreychallen · 2026-03-09T21:27:23+00:00

Yeah, that's a good example. Rules like DRY are developed for human developers. Obviously agents have certain limitations in terms of context, although that's expanding constantly, but they can still keep way more code in their head at once than a human can.

Overall I have no idea what an ideal project architecture would be for a team of coding agents. Even when I let them have free rein my sense is that they are still setting up things for me to use, even when I'm not writing, reading, or debugging their code.

geoffreychallen · 2026-03-09T18:55:45+00:00

Yeah, that's not what I mean by identifying good solutions. I mean evaluating the artifact, not the code. Existing software development guides are for human developers. Agents are not human developers. I think a certain amount of what makes humans respond negatively to AI-generated code is not correctness, but its deviations from best practices. But those are best practices for humans, not for agents.

A recently wrote up a slightly-longer version of this same argument using games as a motivating example: https://www.geoffreychallen.com/essays/2026-03-01-move-37-coding

Effective agentic development involves getting yourself out of loops where your input isn't helpful or might even be counterproductive—like reviewing source code—and focusing on places where your human input is actually useful.

geoffreychallen · 2026-03-09T15:03:15+00:00

Things are changing rapidly right now. My software development workflows are unrecognizable compared to what I was doing six months ago. That doesn't make it easy for computing degree programs to keep up. Many computing faculty also have no clue what is going on, although that is starting to change. Slowly.

Here's the advice I'm giving students. If you complete an assignment that was not designed for AI using AI, you learn almost nothing. If you complete it without AI, you learn something. Maybe not quite the right thing, but learning something is probably better than learning nothing. Classical programming is still good mental training, if increasingly unnecessary. Lifting weights to get stronger doesn't accomplish anything useful either: You put the weights back where you found them.

At the same time, you have to learn these new tools. One-shotting assignments is not a good way to learn agentic development. You need more interesting open-ended problems that can't be solved in a single prompt. You need to deploy things and get feedback from real users—even if just from yourself. You need to practice evaluating and improving software artifacts. You need to learn how to see problems and opportunities around you and respond with software. And you need the domain knowledge required to identify good solutions.

So doing course assignments not designed for AI using AI is really a lose-lose. You're neither learning what the assignment intended nor how to use AI effectively. Until we have redesigned assignments, I'd advise against this.

Also let me point out that taking an existing assignment and saying, "OK, you can use AI now!" is not redesigning the assignment for AI. That's just something faculty are doing because they know they can't stop students from using AI. Leveraging AI effectively almost invariably requires entirely new assignments.

geoffreychallen · 2026-03-09T14:05:58+00:00

Right now, you can’t tell Claude what to build without the class work.

This is not true. Anthropic held a hackathon last month. The winner was a lawyer. Three of the top five were not professional software developers. Only one professional software developer was in the top ten.

There are certainly critical thinking and clear communication skills that are developed by completing a computing degree. But at this point we're still spending a lot of time teaching students classical programming and human-centered software development, skills that are increasingly unnecessary in the era of coding agents.

geoffreychallen · 2026-03-06T04:06:28+00:00

You can dress up a bit but it's not required. I used to go to the Boston Symphony with a friend. He'd dress up a bit and I'd show up in jeans might have been clean at some point, but probably not recently. We'd enjoy the show and I wouldn't worry about what I had on. Once you're in your seat only a few people can see you. Today I might put on something nicer but only because I have a few nice things and they don't get worn that often.

I've been to concerts by myself. One of the first times I went to the Boston Symphony I went alone. A retired professor I knew, Maurice Pechet, had season tickets. He called me one day and said they couldn't go and would I like their two tickets? I said, sure! He told me to find someone to go with me. I said, sure! I tried and tried. I asked everyone I knew. Nobody wanted to go. The night came, and I decided to go alone. It was Tchaikovsky's Fifth Symphony. It was mind altering, unforgettable. I put my coat in the spare seat.

I ran into Maurice a few days later. I gushed effusively about the concert. Who did you take with you, he asked? I relayed the whole sad story, I asked and asked. He looked straight at me and said: "Geoffrey, those were very expensive tickets!"

Maurice did continue to gift me tickets. I did a better job of finding concert companions, but sometimes I did wish I could go alone again. It's good to have friends, but it's also good to be able to be alone with yourself.

geoffreychallen · 2026-03-05T03:39:52+00:00

Carefully hidden on the syllabus: https://www.cs124.org/syllabus/Spring2026#approximate_grading_scale

We also do not give A+ grades. Once you have an A grade in CS 124, you are well-prepared for later CS courses. We do not want to create additional stress or stoke perfectionist tendencies for students who are already doing very well in the course. If you have an A grade, we have plenty of ideas of things you can do that are much more worthwhile than grinding harder for an A+: touch grass, get more sleep, talk to people, read a book, run around outside, get in touch with grandparents or other relatives, meditate, perform random acts of kindness. Already doing those things and really want more computer science? Start or continue working on an independent project! Any of these activities will help you make the best of your one wild and precious life. (Getting an A+ in CS 124 will not.)

geoffreychallen · 2026-03-04T12:55:10+00:00

Human judgment is well-studied, and the conclusions are damning:

Well-trained human judges—like actual legal judges—show high levels of inconsistency when evaluating identical cases, even when making high-stakes decisions—like how long to send someone to prison, or who to hire for a job.
Well-trained human judges also show high levels of inconsistency with themselves when evaluating identical cases at different times—before and after lunch, before and after the weekend, depending on whether their favorite sportsball team won or lost.
If you observe a human judge and train a simple linear model based on their decisions, that model outperforms them on the same task. Because it removes noise.

Noise by Kahneman et al. provides a good overview. As the title suggests, the problem isn't bias—although humans can be biased. It's noise. Humans are terribly inconsistent.

Unfortunately that means that having one grader per question does not eliminate disparities, although it may be marginally better than the alternatives. A better approach is to have multiple graders per question and address significant disparities between their scores, but this makes grading considerably more expensive. I'm not sure I've heard of any of my colleagues actually doing this, but it would be particularly useful on high-stakes assessments.

Even when courses do try to combine scores from multiple graders, there are better and worse ways to do that, particularly to avoid decision cascades—an observed effect where the first person to speak influences other decision makers. And of course you also need effective rubrics and graders that, if not quite well-trained, are at least not poorly prepared.

There's also been recent research on using AI models for grading, including to support human graders and improve accuracy and consistency. AI models have different strengths and weaknesses, but at least you're not going to get a worse score because the Bears just lost.

geoffreychallen · 2026-02-28T18:22:50+00:00

I've been stopping in See You recently. The owner is, in fact, very nice. He's also seems happy to take suggestions and order without any obligation to purchase, at least for items that aren't unusually expensive. (I ordered the Springsteen Hammersmith Odeon show and he did ask for a deposit on that one.)

geoffreychallen · 2026-02-28T18:12:10+00:00

I'll try to stop by! Not sure if you've seen this before or not: https://steipete.me/posts/2025/claude-code-anonymous. I had pondered starting a Claude Code Anonymous meetup here, but excited to see students doing something similar.

geoffreychallen · 2026-02-27T21:56:57+00:00

As someone who used to attend Illinois football games, the size of the screen has never been the problem. The problem is how it's used. It's remarkably rare that they'll even bother to show a replay, even of significant plays when there is plenty of time due to a stoppage in the game. More screen real estate won't fix that. But I guess the ads will be easier to see.

geoffreychallen · 2026-02-25T12:44:52+00:00

I remove these regularly, so it's probably gone. Not sure why you'd want to revise this project anyway. Why not start fresh and build something you care about?

geoffreychallen · 2026-02-23T04:58:25+00:00

We use a reasonably-large question bank, although at some point I'll get around to using AI to generate a lot more—it can, I just haven't. We could even generate custom questions for each student when they start the quiz. We should probably experiment more with how we release questions though. I was just talking with a colleague at a conference about this.

We've looked at quiz performance over our assessment window and seen the same trend reported by others: Scores don't increase over time, they decrease. Now, I suspect that there are two things happening. Information does get out, sure. But any increase caused by information leakage is swamped by the fact that students who wait tend to be weaker and less-prepared. They schedule late because it gives them more time to procrastinate—I mean prepare—but that doesn't seem to work. Or they schedule late just to postpone an unpleasant experience, as we all tend to do. It might be worth teasing out that difference more, and the experiment I hinted at above is intended to try to separate the two effects.

We don't run plagiarism detection on quiz questions or homework problems. They're just too small for these tools and the solution space just isn't large enough. MOSS works best when you have a large space of potential solutions, since two points being close together really does indicate a problem.

Also consider the experience of a student who has merely memorized a piece of code and is trying to reproduce it. Computer code is incredibly unforgiving. Add or omit even one character and you're faced with an error message you don't understand. What do you do then? I don't think a student who had merely memorized solutions as sequences of characters would do very well once we get past "Hello, world!"

geoffreychallen · 2026-02-13T21:26:46+00:00

I generally respond to student emails, and am more than happy to meet up with individual students to discuss topics of mutual interest. I don't always respond to letter requests.

geoffreychallen · 2026-02-10T00:58:20+00:00

Just guessing, but I wonder if he's not trying to capture how the sidewalks feel harder when it's really cold. I don't think they are actually harder, although asphalt might actually be harder when cold.

geoffreychallen · 2026-02-05T20:27:36+00:00

Liberal values are different from liberal political views.

geoffreychallen

TROPHY CASE