Technology

Introducing Students to Text Mining II

Joy4 Comments

In the Fall of 2020, I blogged about how I introduce students to text mining, as part of a data analytics class.

Could Turing ever have imagined that a human seeking customer service from a bank could chat with a bot? Maybe text mining is a big advance over chess, but it only took about one decade longer for a computer (developed by IBM) to beat a human in Jeopardy. Winning Jeopardy requires the computer to get meaning from a sentence of words. Computers have already moved way beyond playing a game show to natural language processing.

https://economistwritingeveryday.com/2020/11/07/introducing-students-to-text-mining/

I told the students that “chat bots” are getting better and NLP is advancing. By July 2020, OpenAI had released a beta API playground to external developers to play with GPT-3, but I did not sign up to use it myself.

In April of 2022, I added some slides inspired by Alex’s post about the Turing Test that included output from Google’s Pathway Languages Model. According to Alex, “It seems obvious that the computer is reasoning.”

This week in class, I did something that few people could have imagined 5 years ago. I signed into the free new GPTChat function in class and typed in questions from my students.

We started with questions that we assumed would be easy to answer:

Then we were surprised that it answered a question we had thought would be difficult:

And then we asked two questions that prompted the program to hedge, although for different reasons.

It seems like the model is smarter than it lets on. For now, the creators are trying hard not to offend anyone or get in the way of Google’s advertising business. Overall, the quality of the answers are high.

Because of when I was born, I believe that something I have published will make it into the training data for these models. Will that turn out to be more significant than any human readers we can attract?

Of course, GPT can still make mistakes. I’m horrified by this mischaracterization of my tweets:

Protests Erupt Across China Over COVID Policy But Lockdowns Continue: Why?

Scott Buchanan1 Comment

Headlines in today’s financial news include items like “Clashes in Shanghai as COVID protests flare across China“ from Yahoo Finance. There have been widespread protests this week, which are normally a rarity under the authoritarian regime, and are being suppressed by any means necessary. Apple stock is down about 4% in the past two trading days on fears that iPhone shortages will get worse due to worker unrest in the giant Foxconn factory in Zhengzhou. Wall Street keeps hoping the China will loosen up, since the lockdowns on the world’s second-largest economy are a drag on global markets.

China has pursued a “zero-COVID” policy, of strict mass lockdowns to halt any spread of the virus. Residents have been confined to their apartments for over 3 months in some cases. Whole cities with tens of millions of people have been locked down for months at a time whenever a number of cases are spotted. China’s economic growth has stagnated, and unemployment among young people has risen to 20%, which has helped fuel unrest.  Chinese people are aware that the rest of the world has moved on from mass lockdowns, and may be realizing the futility of thinking that lockdowns can stave off the virus indefinitely.

Given its discomfort with widespread discontent and protests, why does the Chinese government persist in this policy? An article in the Atlantic by Michael Shuman answers that question: “Zero COVID Has Outlived Its Usefulness. Here’s Why China Is Still Enforcing It. “  Back in 2020 when COVID first swept through the world, the strict lockdowns (readily enforced in an authoritarian regime) seemed like a big win for the Chinese leadership:

When the outbreak began in Wuhan in early 2020, the virus was unknown, vaccines were unavailable, and China’s poorly equipped health system could have quickly become overwhelmed by a sweeping pandemic. Yet the policy had a political element from the very beginning as well. The Communist Party is adept at sniffing out threats to its rule, and it quickly identified COVID as one of them. A major public-health crisis, with millions dying, would have raised serious doubts about the regime’s competence, which is, in effect, its sole claim to legitimacy.

Worse, the party could have faced a populace that directly blamed it for the outbreak—with good reason. The Chinese authorities at both the national and local levels botched their initial response to the novel coronavirus, suppressing information about its discovery by a Wuhan doctor and acting far too slowly to contain the initial spread. Sensing its potential vulnerability, the party shifted into anti-COVID overdrive, shutting down large swaths of the country, with the result that it did succeed in snuffing out an epidemic in a matter of weeks, even as it spread to the rest of the world.

That success allowed the Communist Party to transform a potential tragedy into a public-relations triumph. Within weeks of the Wuhan outbreak, China’s propaganda machine was touting the wonders of its virus-busting methods. And as the U.S. and other Western countries struggled to contain the disease, Beijing’s big win became even more valuable as evidence that its authoritarian system was more capable and caring than any democratic one. Beijing and its advocates pointed to rising case and death counts in the U.S. as proof of China’s superiority and American decline.

A number of other countries including Australia and New Zealand also implemented strict (stricter than in the U.S.) lockdown measures in 2020, and, like China, experienced far less impact from the virus in that timeframe than seen in the U.S. However, most of these measures were lifted in 2021. The widespread application of mRNA vaccines like those from Pfizer and Moderna in the West has served to mitigate the severity of the viral infection. Also, some measure of herd immunity has been achieved by the widespread exposure to COVID in the population; antibodies persist for at least eight months after contracting the disease. So, what’s up with China?

China has resisted using Western vaccines, relying instead on homegrown vaccines which are less effective, though they do give some measure of protection.  Also, “The additional layers of high-tech surveillance adopted in the name of pandemic prevention can be used to enhance the tracking and monitoring of the populace more generally,” which is another win for the government. However, the major factor is that the Party, and especially President Xi, cannot afford to loosen up now and risk an embarrassing explosion of cases that would overburden the healthcare system and probably lead to millions of deaths:

The victory of zero COVID was claimed not just as the party’s but as Xi Jinping’s in particular. The State Council, China’s highest governing body, declared in a 2020 white paper that Xi had “taken personal command, planned the response, overseen the general situation and acted decisively, pointing the way forward in the fight against the epidemic.”

This narrative became entrenched. If Beijing loosened up and allowed COVID to run amok, the Chinese system would appear no better than those of loser democracies, and Xi would seem like another failing politician, a mere mortal, not the virus-fighting superhero he was painted as. Zero COVID’s failure would be a disaster for the Communist Party’s veneer of infallibility.

So the leadership insists on zero COVID and damn the consequences.

Blogging about Tweet Threads

JoyLeave a comment

Elon Musk bought Twitter almost a month ago.

The community I follow was speculating, half-seriously, that Musk has abruptly fired so many employees that the entire site would just crash.

My prediction is that many economists will stay on Twitter because it is such a useful venue for sharing work and ideas. There was also a sizable migration to Mastodon this week where a critical mass of economists will likely remain for a while. I made an account there @JoyBuchanan@econtwitter.net   I don’t think my habits are going to change much right now, meaning I will not add being active on Mastodon to my current slate of activities. Personally, I find Facebook to be a place for meaningful connection in my professional community, as well, but that might be much harder for younger researchers to break into.

Here’s my “What if it all goes down?” moment. I’ll document a great tweet thread by Dennie van Dolder, who is an inspiration for the art form of announcing a working paper on Twitter. (Mastodon does not currently have the thread format, which might point people back to blogging on the margin?)

Dennie van Dolder of the University of Essex provides a tweet thread

I’ll screenshot that thread (just in case).

He also provides a blog post with high production quality and the more traditional SSRN working paper. It’s 2022 and that’s the trifecta for putting work out online, or at least it was.  I have a “News” and a “History” category for classifying these blog posts. Where does this post belong? I settled on “Technology”.

My BlockFi Crypto Account Is Frozen Due to Monster FTX Exchange Blowup

Scott Buchanan1 Comment

About a year ago, I posted some articles touting the use of BlockFi as an alternative checking account. It paid around 9% interest (this was back when interest rates were essentially zero on regular savings accounts), and allowed withdrawal or deposit of funds at any time. Nice. BlockFi is associated with respected firm Gemini, and (unlike many crypto operations) is U.S. based, with consistent formal auditing. They earned interest on my crypto by lending it out to “trusted counter-parties”, always backed by extra collateral. What could possibly go wrong?

In July I wrote about a big cryptocurrency meltdown, in which a number of medium-sized players went bust.  At that time, BlockFi assured its customers that its sound business practices put it above the fray, no problemo. They did make it through that juncture OK. But I withdrew a third of my funds, just to be on the safe side.

The huge news in crypto this past week has been the sudden, total implosion of major exchange FTX (more on that below). FTX is a major business partner with BlockFi. No worries, though, as of Tuesday of last week,  BlockFi COO Flori Marquez tweeted that “All BlockFi products are fully operational”.  Then the hammer dropped: On Thursday (11/10), BlockFi froze withdrawals, due to complications with FTX. My remaining crypto is stranded, most likely for years of legal proceedings, and I may never get it all back. I’m not going to starve, but the amount is enough to hurt.

In this case, I don’t really blame BlockFi – by all accounts, they have been trying to run an honest, responsible business. Before last week, nobody had much reason to think that FTX was totally rotten.  My bad for not connecting the FTX-BlockFi dots earlier, and pulling out more funds when I had the chance.

The Great FTX Debacle

The star of this show is Sam Bankman-Fried, the (former) head of FTX:

James Bailey posted here on EWED on the FTX crash last week. CoinDesk author David Morris summarized the downfall of Bankman-Fried’s crypto empire:

FTX and Bankman-Fried are unique in the stature they achieved before self-immolating. Over the past three years, FTX has come to be widely regarded as a reputable exchange, despite not submitting to U.S. regulation. Bankman-Fried has himself become globally influential, thanks to his thoughts on cryptocurrency regulation and his financial support for U.S. electoral candidates – not necessarily in that order.

… Facts first uncovered by CoinDesk played a major role in the events of the past week. On Nov. 2, reporter Ian Allison published findings that roughly $5.8 billion out of $14.6 billion of assets on the balance sheet at Alameda Research, based on then-current valuations, were linked to FTX’s exchange token, FTT.

This finding, based on leaked internal documents, was explosive because of the very close relationship between Alameda and FTX. Both were founded by Bankman-Fried, and there has been significant anxiety about the extent and nature of their fraternal dealings. The FTT token was essentially created from thin air by FTX, inviting questions about the real-world, open-market value of FTT tokens held in reserve by affiliated entities.

Negative speculation about a financial institution can be a self-fulfilling prophecy, triggering withdrawals out of a sense of uncertainty and leading to the very liquidity problems that were feared.

Customers started a “run on the bank”, withdrawing billions of dollars of assets, leading to total insolvency of FTX:

The Financial Times reported that FTX held approximately $900 million in liquid crypto and $5.4 in illiquid venture capital investments against $9 billion in liabilities the day before it filed for bankruptcy.

If FTX had been run as an honest exchange, this withdrawal should not have been too much of a problem – – just give customers back the coins they had deposited with FTX. Apparently, though, FTX had taken customer assets and transferred them over to a sister company, Alameda, to trade with. The valuable customer crypto assets left the FTX balance sheet, and were largely replaced by the self-generated (and now nearly worthless) FTT token:

It remains worryingly unclear, though, exactly why even such a dramatic rush for the exits would have led FTX to seek its own bailout. The exchange promised users that it would not speculate with cryptocurrencies held in their accounts. But if that policy was followed, there should have been no pause to withdrawals, nor any balance sheet gap to fill. One possible explanation comes from Coinmetrics analyst Lucas Nuzzi, who has presented what he says is evidence that FTX transferred funds to Alameda in September, perhaps as a loan to backstop Alameda’s losses.

It doesn’t help that on Friday (11/11) some $477 million was outright stolen from FTX wallets. (The Kraken exchange said it has identified the thief and are working with law enforcement).

Where does the FTX saga go from here? There seems little in the way of assets left for the bankruptcy judge to distribute to former customers and creditors. In the case of BlockFi, they are dependent on a $400 million line of credit extended to them by FTX back in June, to keep operating. And who knows how much of BlockFi assets were stored with FTX – – since FTX was to be their white knight, BlockFi would not be in a position to withdraw deposits from FTX like other customers did.

I predict that nothing really bad will happen to Bankman-Fried and his buddies who ran this thing. Although its operation was apparently dishonest, it is not clear how much is subject to U.S. federal or state legal jurisdiction. Bankman-Fried and friends ran their empire from a big apartment suite in the Bahamas. Plus, he is pretty well-connected. Beside his massive campaign contributions, his business and sometimes romantic partner Caroline Ellison (she is CEO of Alameda) is the daughter of MIT professor Glenn Ellison, the former boss (as colleagues at MIT) of the U.S. Securities and Exchange Commission chair Gary Gensler. These relations were captured in an impish tweet by Elon Musk:

Two Types of News: Elections vs Crashes

James Bailey2 Comments

Some events are like elections: it was obvious that some big political news would break on Election Day, we just had to wait to find out what exactly would happen. Others are like market crashes: you might know in principle they’re a thing that can happen, but you don’t really expect any particular day to be the day one happens, so they seem to come out of the blue. As it turns out, for one of the largest crypto exchanges the day of the crash also happened to be Election Day.

FTX.com is facing a bank run sparked by competitor Binance tanking the price of the token that backed some of their assets. Customers are having issues withdrawing their money, Binance has withdrawn its offer to bail out FTX by taking them over, and bankruptcy seems likely. Supposedly this doesn’t affect Americans using FTX US, but I’d be nervous about any funds I had there, or indeed with funds in any centralized crypto exchange or stablecoin (Tether and even USDC seem to be having issues holding their pegs). All this was especially shocking because many considered FTX founder Sam Bankman-Fried one of the most trustworthy people in the often sketchy world of crypto. He was always meeting with US regulators and lawmakers, and seems not to be motivated by greed; he had already begun to give away his fortune at scale.

After any surprising event like this, some people claim it was actually obvious and they saw it coming (despite usually never having said so beforehand), while others start looking back for warning signs they missed. The most interesting one is something that shocked me when I first heard it March, but I never considered the risk it implied for FTX until the crash:

Going forward, red flags to watch out for seem to be topping a list of youngest billionaires (as Elizabeth Holmes also did) and buying naming rights to a stadium.

In contrast to this crash, the election happened right when we all expected, and at least largely how I expected. Like markets, I underestimated Democrats a bit; polls overall were impressively accurate this year, though they of course missed on some particular races. Votes are still being counted, and as of now we don’t even know for sure which party will control Congress (PredictIt currently gives Democrats a 90% chance in the Senate and a 20% chance in the House). But here are some early attempts to assess forecast accuracy. As I said, some polls were quite good:

Some polls weren’t so good, which means its important to weight better pollsters more heavily when you aggregate them. Some attempts at that were also quite good:

Oddly, some no money (Metaculus) / play money (Manifold Markets) forecasting sites seem to have done better than the real-money prediction sites:

The Sins of TikTok, Part 1: Extreme Privacy Theft by China-Based Company

Scott Buchanan1 Comment

Social media apps are nosy by nature; it is no secret that their main business model is to snoop out information about you, the user, and package and sell that information to advertisers who can target you. But there is one wildly popular app which goes beyond the norms of intrusiveness and privacy invasion AND is targeted largely at children and adolescents AND is based in China and thus is subject to Big Brother’s request for any and all data. That app is TikTok.

To avoid a bunch of re-wording, I will largely share excerpts from “ The Privacy Risks of TikTok – Why This Invasive App is So Dangerous “ by Priscilla Sherman at VPNOverview. Other articles echo her concerns with TikTok:

TikTok is an extremely popular social media video app owned by the Chinese tech company ByteDance. On TikTok, users can create and share short-form videos using a variety of filters and effects. The platform is full of dancing, comedy, and other entertaining videos….

Several agencies and news outlets are now sounding the alarm and reporting on the many problems that have surfaced. ByteDance claims to want to break away from its Chinese background in order to serve a global audience and says it will never share data with the Chinese government. This claim, however, seems impossible now that new security laws have been introduced in Hong Kong.

TikTok’s user base mostly consists of children and adolescents, which many consider to be vulnerable groups. This is a main reason for different authorities to express their worries. However, it isn’t just the youth that might be in danger from TikTok. From December 2019 onwards, U.S. military personnel were no longer allowed to use TikTok, as the app was considered a ‘cyber threat’…

[Hacker group] Anonymous has published a video listing the many dangers of TikTok. They quote a source that has done extensive research on TikTok: “Calling it an advertising platform is an understatement. TikTok is essentially malware that is targeting children. Don’t use TikTok. Don’t let your friends and family use it. Delete TikTok now […] If you know someone that is using it, explain to them that it is essentially malware operated by the Chinese government running a massive spying operation.”

These claims fit in with the recent developments surrounding TikTok. For example, Apple researchers announced that TikTok deliberately spies on users.

Claims keep piling up, showing that TikTok is a very invasive application that poses a substantial privacy risk. It seems that the data collection at TikTok goes much further than other social platforms such as Facebook or Instagram. This is surprising, since both of these companies have already faced backlash for the way they’ve dealt with user privacy. TikTok seems to collect data on a much larger scale than other social media platforms do. This, combined with TikTok’s origins makes it quite plausible that the Chinese government has insight into all of this collected data…..

Research from a German data protection website has revealed that TikTok installs browser trackers on your device. These track all your activities on the internet. According to ByteDance, these trackers were put in place to recognize and prevent “malicious browser behavior”. However, they also enable TikTok to use fingerprinting techniques, which give users a unique ID. This enables TikTok to link data to user profiles in a very targeted way.

Unfortunately, this happens with a great disregard of privacy – perhaps intentionally so. The German researchers indicate, for example, that IP addresses aren’t anonymized when TikTok uses Google Analytics, meaning your online behavior is directly linked to your IP address. An IP address provides information about your location and, indirectly, about your identity…

A user on Reddit used reverse engineering to figure out more about TikTok. Anonymous quoted the results in the video we mentioned earlier. The Reddit user discovered that TikTok collects all kinds of information:

  • Your smartphone’s hardware (CPU type, hardware IDs, screen size, dpi, memory usage, storage space, etc.);
  • Other apps installed on your device;
  • Network information (IP, local IP, your router’s MAC address, your device’s MAC address, the name of your Wi-Fi network);
  • Whether your device was rooted/jailbroken;
  • Location data, through an option that’s turned on automatically when you give a post a location tag (only happens on some versions of TikTok);

Additionally, the app creates a local proxy server on your device, which is officially used for “transcoding media”. However, this is done without any form of authentication, making it susceptible to misuse….

We asked investigative journalist and writer Maria Genova about her vision on TikTok. … Genova says: “There’s a reason several countries have banned it. It’s unbelievable how much information an app like that pulls from your phone”…

TikTok needs access to your camera and microphone in order to work properly… However, there aren’t any specifications explaining how exactly these permissions are used. Therefore, TikTok could theoretically record conversations and sounds using your microphone, even when you aren’t filming a TikTok video.

We could go on and on with the technical details here, but you get the point. The fact that “IP addresses aren’t anonymized“ is really a big, bad deal. The article concludes:

The current findings and concerns surrounding TikTok are reason enough for us [the staff at VPNOverview] to remove the app from our devices. Whether TikTok’s main target group – young people between 14 and 25 – is sensitive to the privacy concerns that have come to light, remains to be seen.

Indeed.

One more quote , from Brendan Carr of the U.S. Federal Communications Commission (FCC), regarding the reliability of TikTok’s claims that they do not share data with the Chinese government:

“China has a national security law that compels every entity within its jurisdiction to aid its espionage and what they view as their national security efforts,” Carr said earlier this year, alluding to the fact that Chinese companies must make all the data they collect available to the Chinese Communist Party (CCP).

Stay tuned for Part 2, dealing with some larger market ramifications of TikTok’s evasion of  Apple and Android privacy protections.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

This just in from BuzzFeed (added to original post here):

“Leaked Audio From 80 Internal TikTok Meetings Shows That US User Data Has Been Repeatedly Accessed From China”

For years, TikTok has responded to data privacy concerns by promising that information gathered about users in the United States is stored in the United States, rather than China, where ByteDance, the video platform’s parent company, is located. But according to leaked audio from more than 80 internal TikTok meetings, China-based employees of ByteDance have repeatedly accessed nonpublic data about US TikTok users — exactly the type of behavior that inspired former president Donald Trump to threaten to ban the app in the United States.

The recordings, which were reviewed by BuzzFeed News, contain 14 statements from nine different TikTok employees indicating that engineers in China had access to US data between September 2021 and January 2022, at the very least. Despite a TikTok executive’s sworn testimony in an October 2021 Senate hearing that a “world-renowned, US-based security team” decides who gets access to this data, nine statements by eight different employees describe situations where US employees had to turn to their colleagues in China to determine how US user data was flowing. US staff did not have permission or knowledge of how to access the data on their own, according to the tapes.

“Everything is seen in China,” said a member of TikTok’s Trust and Safety department in a September 2021 meeting.

How to Magnetize a Screwdriver (So It Holds onto a Screw)

Scott BuchananLeave a comment

This is an economics blog; here is a life hack that can save you some money, and maybe time.  It can be really helpful to have your screwdriver magnetized, so a screw will stick to it. This past weekend I helped someone repair a microwave door, and for re-assembly I had to get a screw into its hole, where its hole was recessed in a narrow space where I could not have held the screw with my fingers whilst starting it with the screwdriver. So it was very helpful to just stick the screw on the end of the tool, and (carefully) insert the tip of the screw into its threaded hole and just start turning. Likewise, it was helpful in disassembly to be able to draw a screw out with the magnetized tip.

You can go buy a set of magnetized screwdrivers from Amazon. But these get mixed reviews and of course cost money and shipping delay and now you have more screwdrivers to store. A comment in one of the Amazon reviews clued me in that you can easily magnetize a screwdriver which you already have. Here is how:

( 1 ) Start with a strong magnet – – maybe a single magnet that you happen to have, or make a stack of say five medium sized disk refrigerator magnets. Techies can remove magnets from an old speaker or hard drive.

( 2 ) Using only one end (pole) of your magnet, draw it along the  screwdriver shaft, from the top or middle out to the end, always in the same direction. Do this maybe four times, then rotate the screwdriver a quarter turn, then make another four strokes, and so on for all four sides of the screwdriver. You’re done.

I did this, and it worked great. A couple of further comments – – first, if there is no rubbery coating on your magnet and you don’t want to scratch up the finish on your screwdriver, you could put a single layer of  masking tape or painters tape on the part of the magnet that is scraping along the screwdriver. Second, the hard steel of the screwdriver is not a great permanent magnet. You might need to do this again in a year, and you will never get a really strong magnetic effect (this may be why there were some complaints on Amazon). Also, if you give the screwdriver some sharp taps (or drop it on concrete floor), it can rescramble the magnetic domains and lose  magnetic orientation in the steel, so again you’d have to repeat the treatment.

You can also magnetize a screwdriver by wrapping a coil of insulated wire around it, and hooking the wire up to a battery. Also, you can make the screwdriver magnetic temporarily by sticking a disk magnet on the shaft.

I suppose you could bring your magnet to your friend’s house and process his or her favorite screwdriver next time you go over for some other reason. Or you could make magnetized screwdrivers for gifts.

Some references:

https://www.wikihow.com/Magnetize-a-Screwdriver

https://www.instructables.com/How-to-Magnetize-a-Screwdriver-at-Home/

Bonus hack: How to Sanitize Face Masks

Now we are back to being able to buy KN95 and (even better) KF94 face masks, if a mask gets too breathed in, we can just throw it out and get a new one. But if for some reason (a new pandemic apocalypse like 2020?) you need to disinfect a face mask, there are ways.

Most flu and coronaviruses cannot live indefinitely on a dry surface. So one approach is simply to put each mask in its own dry paper bag (to prevent contact with more virus particles) and leave in a dry, preferably warm place for 3 days.

If you are in a hurry, apparently heating for 60 minutes at  the oven at 70°C (158°F) will also do the trick.

Reference: https://smartairfilters.com/en/blog/disinfect-clean-n95-mask-virus-coronavirus/

An intervention for children to change perceptions of STEM

Joy1 Comment

Here is a a new paper related to the topic of women getting into technical fields (see previous post on my paper about programming).

Grosch, Kerstin, Simone Haeckl, and Martin G. Kocher. “Closing the gender STEM gap-A large-scale randomized-controlled trial in elementary schools.” (2022).

These authors were thinking about the same problem at the same time, unbeknownst to me. In their introduction they write, “We currently know surprisingly little about why women still remain underrepresented in STEM fields and which interventions might work to close the gender STEM gap.”

My conclusion from my paper is that, by college age, subjective attitudes toward tech are very important. This leads to the questions of whether those subjective attitudes are shaped at younger ages. Grosch et al. have run an experiment to target 3rd-graders with a STEM-themed game. I’ll quote their description:

The treatment web application (treatment app) intends to increase interest in STEM directly by increasing knowledge and awareness about STEM professions and indirectly by addressing the underlying behavioral mechanisms that could interfere with the development of interest in STEM. The treatment app presents both fictitious and real STEM professionals, such as engineers and programmers, on fantasy planets. Accompanied by the professionals, the children playfully learn more about various societal challenges, such as threats from climate change and to public health, and how STEM skills can contribute to combating them. The storyline of the app comprises exercises, videos, and texts. The app also informs children about STEM-related content in general. To address the behavioral mechanisms, the app uses tutorials, exercises, and (non-monetary) rewards that teach children a growth mindset and improve their self-confidence and competitive aptitude. Moreover, the app introduces female STEM role models to overcome stereotypical beliefs. To test the app’s effect, we recruited 39 elementary schools in Vienna (an urban area) and Upper Austria (a predominantly rural area).

This is a preview of their results, although I recommend reading their paper to understand how these measurements were made:

Girls’ STEM confidence increases significantly in the treatment group (difference: 0.047 points or 0.28 standard deviations, p = 0.002, Wald test), and the effect for girls is significantly larger than the effect for boys.

Result 2: Children’s competitiveness is positively associated with children’s interest in STEM. We do not find evidence that stereotypical thinking and a growth mindset is associated with STEM interest.

Lastly, my kids play STEM-themed tablet games. PBS Kids has a great suite of games that are free and educational. Unfortunately, I have not tried to treat one kid while giving the other kid a placebo app, so my ability to do causal inference is limited.

Cheers to Sumproduct!

Zachary Bartsch2 Comments

I teach macroeconomics, finance, and other things.

Often, I use Excel to complete repetitive calculations for my students. The version that I show them is different from the version that I use. They see a lot more mathematical steps displayed in different cells, usually with a label describing what it is. But when I create an answer calculator or work on my own, I usually try to be as concise as possible, squeezing what I can into a single cell or many fewer cells. That’s what brings me to to the sumproduct excel function that I recently learned. It’s super useful I’ll illustrate it with two examples.

Example 1) NGDP

One way to calculate NGDP is to sum all of the expenditures on the different products during a time period. The expenditures on a good is simply the price of the good times the quantity that was purchased during the time period. The below image illustrates an example with the values on the left, and the equations that I used on the right. That’s the student version. There is an equation for each good which calculates the total expenditure on the individual goods. Then, there is a final equation which sums the spending to get total expenditures, or NGDP.

Continue reading →

Bounce Houses are Surprisingly Cheap

James BaileyLeave a comment

Last year was the first time I saw a family that owned their own bounce house and just set it up in their living room. At the time I thought, what a lucky rich kid, that must cost at least a thousand dollars. But my wife looked into it and found out that bounce houses are surprisingly cheap these days. She got our kids this one last Christmas, its currently going for $234 on Amazon:

The kids love it and its still going strong ten months later, despite substantial use from kids and the presence of two sharp-clawed cats. It was certainly a bigger hit than the other major gift we tried last Christmas- telescopes are surprisingly hard to use.