Teaching

Teaching Business Statistics Graphs with Chart Crimes

Joy Buchanan1 Comment

Many people take a basic statistics course in college. Those course usually include an overview of standard graphs and best practices for visualizing data.

To keep that section from getting boring (“here’s a line graph… here’s a bar chart…”) you can borrow my slides on #chartcrimes  Teaching people best practices is more engaging when you can show real examples of charts gone wrong.

These are pictures I dropped directly into slides and talked through:

P.S. Joke I made about this section of my textbook:

Older post about teaching stats to Gen Z: Probability Theory for the Minecraft Generation

Is AI learning just MOOCs again?

Joy Buchanan2 Comments

I created a provocative title for fun. Tyler pointed me to this podcast:

Joe Liemandt  – Building Alpha School, and The Future of Education (Apple podcast link)

I suppose I’m sold on their claim that most kids can learn basic facts and some academic skills from an iPad app. Listen all the way through if you are going to listen at all, because even some cracks in the tech product are revealed after the big pitch in the beginning.

I have been using Duolingo to review my high school French and Spanish. I think the few minutes a day I spend have helped drag some vocabulary back out of long-term storage. Although, as I recently heard a comedian say, “All my friends who have Duolingo are still speaking English to me.”

Folks should consider whether AI learning apps is just MOOCs again. Essentially, they need to get kids to watch (short, this time) videos of lecture content. MOOCs were longer lecture content videos. Maybe shorter is the key, combined with personalized feedback. Maybe not, for getting cheap effective comprehensive education that scales.

Last year I wrote Why Podcasts Succeeded in Gaining Influence Where MOOCs Failed

About half an hour in, Liemandt asserts that anyone in America would agree that kids learn life skills through “sports” not school. That’s an oversimplification, but I agree that sports ranks higher than “math class” for developing leadership ability.

Since they at Alpha School believe that have solved quickly learning facts, it’s interesting to hear how they do the rest of “education.” The school must fill enough time that the parents don’t have to see their kids half the day and also teach leadership/ communication/character. Alpha school is expensive ($40,000 a year) and there are many paid adults involved who are called “guides and coaches.”

The extracurriculars that Alpha school offers sounds a lot like what most kids can do in some form at a good public middle school or high school in America.  I wrote about the value of outside-class activities in college here: The Value of Student Organizations and On-Campus Education: Anecdotal Evidence from Tim Keller

My students at Samford are especially good at taking on leadership roles and creating a thriving community. Residential college provides a good testing ground for leadership and there are real “market tests” of success for things like sorority events, as the Alpha school encourages for older kids.

I applaud people trying to innovate. I think we’ll see more educational apps in schools, and that will be great. I’m not trying to dump on Alpha School. I just think the underperformance arc of MOOCs should temper our enthusiasm.

Students still need to learn principles

Joy Buchanan1 Comment

Sometimes I get weeks in the summer that are more research focused. This past week is very much a teaching and service focused week at my university. I haven’t had any time to ponder topics related to research or current events. So, I will share what I’ve been telling my fellow college educators. This will sound backward to some and like common sense to others. Feel free to comment with your thoughts.

College professors who teach 200-level or “principles” classes should not change all that much in response to AI. Students still need to know something. There need to be a few concepts and vocabulary words in their heads. For example, a person cannot use a calculator effectively if they do not know what a square root is at all.

I see highly trained mid-career professionals bragging about how they get ChatGPT to do their work. Can a 20-year-old do that if they don’t know what words to use in a prompt? How does vibe coding go for people who never learned to write out a single line of code? (not a question I have an expert answer to right now)

We should largely be sticking to the “old ways” and at least to some extent still require memorization. Having an exam on paper is a good way to ensure that the students can form coherent thoughts of their own, when possible.

Indeed, students might become AI jockeys when they get to the workplace. A 400-level class would be a good place for them to start heavily integrating AI tools to accomplish tasks and do projects. For anyone unfamiliar with American college categories, that would mean that an undergraduate might heavily use AI tools in their 4th and final year of study.

AI makes a great tutor for learning and enforcing principles, but it should not serve as a replacement test-taker. A human who cannot read and write will not be able to take full advantage of an intelligent machine in the next decade. Voice recognition is getting very good and the models are getting more agentic, so this might all change if we can keep the data centers on long enough. In the future, you might argue that having students write an exam answer by hand is as superfluous as teaching them to play the violin.

As of 2025, what you might see is some teachers who feel pressured to claim they are integrating AI more than they actually want to. A relative I talked to his summer in a corporate job told me that she feels intense pressure at work to be able to claim that she’s using AI. Anyone doesn’t have the appearance of embracing AI looks behind or expendable!

Organization of the Federal Reserve – OR, Why The President is Impotent against the Fed

Zachary Bartsch3 Comments

In my recent post that included Federal Reserve political independence, I dared to use the word ‘trust’, and commenters let me know that they were not pleased about it. In strict economic terms, there is no such thing as trust. Either that, or it’s the same thing as expectations or maybe low-information expectations. Since it wasn’t the main thrust of my post, I didn’t lay-out the informed reasoning behind my confidence in President Trump’s inability to cause Argentina or Turkey or even 1970’s US levels of political influence on the Fed.

In short, I’m not worried about it because the operational structure of the Fed and the means by which individuals join the Fed are determined by congress and are pretty robust. Below is a diagram that I made. I know that it’s a lot, but I’ll explain below.

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I’m Chair! 😬

Zachary Bartsch2 Comments

As of July 1st of this year, I am the Chairman of the Department of Economics at my university. It’s one of those positions that includes more work and not much compensation. Depending on who I tell, I’m given both congratulations and condolences. Generally, at my university there is an expectation that department faculty ‘take turns’ being chair. So, we’re expected to serve whether the pay is good or not. There’s a lot of informal practice around this process.

In addition, Economics Majors have been less popular at liberal arts institutions over the past several years. No one knows why and there are probably multiple reasons. At my institution, our department has healthy enrollment among the peripheral majors. So, the Economics BA and BS have lower enrollment, but the Business Economics and the Global Affairs majors are more popular than ever.

All the same, I’d like to increase the number of students who have declared majors in our department and the number of Economics graduates. How do I do that?

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We’re All Magical

Zachary BartschLeave a comment

The widespread availability and easy user interface of artificial intelligence (AI) has put great power at everyone’s fingertips. We can do magical things.

Before the internet existed we would use books to help us better interpret the world.  Communication among humans is hard. Expressing logic and even phenomena is complex. This is why social skills matter. Among other things, they help us to communicate. The most obvious example of a communication barrier is language. I remember having a pocket-sized English-Spanish dictionary that I used to help me memorize or query Spanish words. The book helped me communicate with others and to translate ideas from one language to another.

Math books do something similar but the translation is English-Math. We can get broader and say that all textbooks are translation devices. They define field-specific terms and ideas to help a person translate among topic domains, usually with a base-language that reaches a targeted generalizability. We can get extreme and say that all books are translators, communicating the content of one person’s head to another.

But sometimes the field-to-general language translation doesn’t work because readers don’t have an adequate grasp of either language. It isn’t necessarily that readers are generally illiterate. It may be that the level of generality and degree of focus of the translation isn’t right for the reader. Anyone who has ever tried to teach anything with math has encountered this.  Students say that the book doesn’t translate clearly, and the communication fails. The book gets the reader’s numeracy or understood definitions wrong. Therefore, there is diversity among readers about how ‘good’ a textbook is.

Search engines are so useful because you can enter some keywords and find your destination, even if you don’t know the proper nouns or domain-specific terms. People used to memorize URLs and that’s becoming less common. Wikipedia is so great because if you want to learn about an idea, they usually explain it in 5 different ways. They tell the story of who created something and who they interacted with. They describe the motivation, the math, the logic, the developments, and usually include examples. Wikipedia translates domain-specific ideas to multiple general languages of different cognitive aptitudes or interests. It scatters links along the way to help users level-up their domain-specific understanding so that they can contextualize and translate the part that they care about.

Historical translation technology was largely for the audience. More recently, translation technology has empowered the transmitters.

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EconTalk Extra on Daisy Christodoulou

Joy Buchanan1 Comment

I wrote an Extra for the How Better Feedback Can Revolutionize Education (with Daisy Christodoulou) episode.

Can Students Get Better Feedback? is the title of my Extra.

Read the whole thing at the link (ungated), but here are two quotes:

For now, the question is still what kind of feedback teachers can give that really benefits students. Daisy Christodoulou, the guest on this episode, offers a sobering critique of how educators tend to give feedback in education. One of her points is that much of the written feedback teachers give is vague and doesn’t actually help students improve. She shares an example from Dylan William: a middle school student was told he needed to “make their scientific inquiries more systematic.” When asked what he would do differently next time, the student replied, “I don’t know. If I’d known how to be more systematic, I would have been so the first time.” 

Christodoulou also turns to the question many of us are now grappling with: can AI help scale meaningful feedback?

An Egg-cellent Consumer Surplus Calculation?

Zachary BartschLeave a comment

There was a recent Planet Money Podcast episode that includes a fun exercise. An NPR employee produces a dozen chicken eggs and wants to sell them at cost to another employee for $5. That’s the setup. How does the employee decide who should receive the eggs? Clearly, the price mechanism won’t work since the price is fixed. A lottery is also not allowed. The egg recipient could engage in arbitrage, reselling the eggs for a higher price. But that’s not very likely and would be socially awkward. The egg producer wants to make someone happy. Who would he make the happiest?

That’s the challenge that the Planet Money team tries to solve.

First, they started with a survey. Rather than asking coworkers to rank a long list of things that includes eggs, the survey adopts a more robust method of pairwise comparisons. Do you prefer toast vs eggs? Eggs vs oatmeal? Toast vs oatmeal? and so on. One problem that they encounter, however, is that there is a lot of diversity among preparations methods. My oatmeal is better than my eggs. But my brother’s oatmeal is not. As it turns out, there is not a standard quality of prepared oatmeal and prepared eggs. So the survey is a flop.

Then they consult an economist. They decide to try to measure “willingness to pay”, which is an economic concept that identifies the maximum that a person could pay for something without becoming worse off. They couldn’t really ask the coworkers what their WTP is. People are social creatures and have many reasons to lie, mislead, signal, and to simply not know. Since someone’s WTP reflects preferences and values, we need a way to solicit the true preference while avoiding lies and most mistakes. Here’s how the economist suggested that they reveal the coworker preferences.

  • Step 1: Tell the coworker these rules.
  • Step 2: Coworker reports their WTP for a single egg in dollars
  • Step 3: A random price will be chosen by a machine. If the price is above the self-reported WTP, the coworker is not allowed to buy the egg. If the price is below the WTP, then the coworker must buy the egg at the random price.

The idea is as follows.

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It’s the Humidity

Zachary Bartsch1 Comment

Recently, I learned what humidity is. That might sound stupid, so let me clarify. I knew that humidity is the water content of the air. I also knew that the higher the number, the more humid. Finally, I also knew that the dew point is the temperature at which the water falls out of the air. But, now I understand all of this in a way that I hadn’t previously.

First, what does it mean for there to be 70% humidity? As it turns out, it’s a moving target. There are two types of humidity: specific and relative. Specific humidity is the mass of water in, say, a kilogram of air. So, more humidity means more water. This is obvious. There’s a related concept called absolute humidity, which is more like mass of water per volume of air (sometimes used in place of specific humidity). Again, more humidity means more water. Neither of these is the way that humidity is reported on the weather channel.

Relative humidity is the number that you see in your weather app. What’s that? Relative to what? First, we need to know that warm air can hold more water than cool air. Pressure also matters, but atmospheric pressure doesn’t change enough to make its effect on humidity significant on relevant margins. So, all of this discussion, and the number in your phone, is at atmospheric pressure. Below is a graph that illustrates the maximum amount of water that can be in the air at different temperatures (red line). So, at 30 degrees Celsius (86 degrees Fahrenheit), there can be as much as 27 grams (0.95 oz or ~2 tablespoons) of water in the air.

More after the jump.

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RGDP Underestimates Welfare

Zachary BartschLeave a comment

Like many Principles of Macroeconomics courses, mine begins with an introduction to GDP. We motivate RGDP as a measure of economic activity and NGDP as an indicator of income or total expenditures. But how does more RGDP imply that we are better off, even materially? One entirely appropriate answer is that the quantities of output are greater. Given some population, greater output means more final goods and services per person. So, our real income increases.  But what else can we say?

First, after adjusting for price changes, we can say that GDP underestimates the value that people place on goods and services that are transacted in markets. Given that 1) demand slopes down and 2) transactions are consensual, it stands to reason that everyone pays no more than their maximum value for things. This implies that people’s willingness to pay for goods surpasses their actual expenditures. Therefore, RGDP is a lower bound to the economic benefits that people enjoy. Without knowing the marginal value that people place on all quantities less than those that they actually buy, we have no idea how much more value is actually provided in our economy.

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