In a recent post about trading stuff for money, I mentioned: Europe had a [blood plasma] shortage of around 38%, which it met by importing plasma from paid donors in the United States, where blood products account for 2% of all exports by value. The internet’s reaction was: “TWO PERCENT?” “TWO PERCENT OF U.S. EXPORTS ARE BLOOD!?” Well, I took that 2% number from a 2024 article in the Economist: Last year American blood-product exports accounted for 1.8% of the country’s total goods exports, up from just 0.5% a decade ago—and were worth $37bn. That makes blood the country’s ninth-largest goods export, ahead of coal and gold. All told, America now supplies 70% or so of the plasma used to make medicine. I figured the Economist was trustworthy on matters of economics. But note: That 1.8% number is for blood products, not just blood. It’s a percentage of goods exported, excluding services. It’s wrong. The article doesn’t explain how they arrived at 1.8%. And since the Economist speaks in the voice of God (without bylines), I can’t corner and harass the actual journalist. I’d have liked to reverse-engineer their calculations, but this was impossible since the world hasn’t yet caught on that they should always show lots of digits. So what’s the right number? In 2023, total US goods exports were $2,045 billion, almost exactly ⅔ of all exports, including services. How much of that involves blood? Well, the government keeps statistics on trade based on an insanely detailed classification scheme. All goods get some number. For example, dirigibles fall under HTS 8801.90.0000: Leg warmers fall under HTS 6406.99.1530: So what about blood? Well, HTS 3002 is the category for: Human blood; animal blood prepared for therapeutic, prophylactic or diagnostic uses; antisera and other blood fractions and modified immunological products, whether or not obtained by means of biotechnological processes; vaccines, toxins, cultures of micro-organisms (excluding yeasts) and similar products: The total exports in this category in 2023 were 41.977 billion, or 2.05% of all goods exports. But that category includes many products that don’t require human blood such as most vaccines. To get the actual data, you need to go through a website maintained by the US Trade Commission. This website has good and bad aspects. On the one hand, it’s slow and clunky and confusing and often randomly fails to deliver any results. On the other hand, when you re-submit, it clears your query and then blocks you for submitting too many requests, which is nice. But after a lot of tearing of hair, I got what seems to be the most detailed breakdown of that category available. There are some finer subcategories in the taxonomy, but they don’t seem to have any data. So let’s go through those categories. To start, here are some that would seem to almost always contain human blood: Category Description Exports ($) Percentage of US goods exports 3002.12.00.10 HUMAN BLOOD PLASMA 5,959,103,120 0.2914% 3002.12.00.20 NORMAL HUMAN BLOOD SERA, WHETHER OR NOT FREEZE-DRIED 38,992,251 0.0019% 3002.12.00.30 HUMAN IMMUNE BLOOD SERA 5,608,090 0.0003% 3002.12.00.90 ANTISERA AND OTHER BLOOD FRACTIONS 4,808,069,119 0.2351% 3002.90.52.10 WHOLE HUMAN BLOOD 22,710,898 0.0011% TOTAL (YES BLOOD) 10,834,483,478 0.5298% Next, there are several categories that would seem to essentially never contain human blood: Category Description Exports ($) Percentage of US goods exports 3002.12.00.40 FETAL BOVINE SERUM (FBS) 146,026,727 0.0071% 3002.42.00.00 VACCINES FOR VETERINARY MEDICINE 638,191,743 0.0312% 3002.49.00.00 VACCINES, TOXINS, CULTURES OF MICRO-ORGANISMS EXCLUDING YEASTS, AND SIMILAR PRODUCTS, NESOI 1,630,036,341 0.0797% 3002.59.00.00 CELL CULTURES, WHETHER OR NOT MODIFIED, NESOI 79,384,134 0.0039% 3002.90.10.00 FERMENTS 361,418,233 0.0177% TOTAL (NO BLOOD) 2,869,107,296 0.1403% Finally, there are categories that include some products that might contain human blood: Category Description Exports ($) Percentage of US goods exports 3002.13.00.00 IMMUNOLOGICAL PRODUCTS, UNMIXED, NOT PUT UP IN MEASURED DOSES OR IN FORMS OR PACKINGS FOR RETAIL SALE 624,283,112 0.0305% 3002.14.00.00 IMMUNOLOGICAL PRODUCTS, MIXED, NOT PUT UP IN MEASURED DOSES OR IN FORMS OR PACKINGS FOR RETAIL SALE 5,060,866,208 0.2475% 3002.15.01.00 IMMUNOLOGICAL PRODUCTS, PUT UP IN MEASURED DOSES OR IN FORMS OR PACKINGS FOR RETAIL SALE 13,317,356,469 0.6512% 3002.41.00.00 VACCINES FOR HUMAN MEDICINE, NESOI 7,760,695,744 0.3795% 3002.51.00.00 CELL THERAPY PRODUCTS 595,963,010 0.0291% 3002.90.52.50 HUMAN BLOOD; ANIMAL BLOOD PREPARED FOR THERAPEUTIC, PROPHYLATIC OR DIAGNOSTIC USES; ANTISERA AND OTHER BLOOD FRACTIONS, ETC. NESOI 914,348,561 0.0447% TOTAL (MAYBE BLOOD) 28,273,513,104 1.3826% The biggest contributor here is IMMUNOLOGICAL PRODUCTS (be they MIXED or UNMIXED, PUT UP or NOT PUT UP). The largest fraction of these is probably antibodies. Antibodies are sometimes made from human blood. You may remember that in 2020, some organizations collected human blood from people who’d recovered from Covid to make antibodies. But it’s important to stress that this is quite rare. Human blood, after all, is expensive. So—because capitalism—whenever possible animals are used instead, often rabbits, goats, sheep, or humanized mice. I can’t find any hard statistics on this. But I know several people who work in this industry. So I asked them to just guess what fraction might include human blood. Biologists don’t like numbers, so this took a lot of pleading, but my best estimate is 8%. When looking at similar data a few years ago, Market Design suggested that immunoglobulin products might also fall under this category. But as far as I can tell this is not true. I looked up the tariff codes for a few immunoglobulin products, and they all seem to fall under 3002.90 (“HUMAN BLOOD; ANIMAL BLOOD PREPARED FOR THERAPEUTIC, PROPHYLATIC OR DIAGNOSTIC USES; ANTISERA AND OTHER BLOOD FRACTIONS, ETC. NESOI”). What about vaccines or cell therapy products? These almost never contain human blood. But they are sometimes made by growing human cell lines, and sometimes those cell lines require human blood serum to grow. More pleading with the biologists produced a guess that this is true for 5% of vaccines and 80% of cell therapies. Aside: Even if they do require blood serum, it’s somewhat debatable if they should count as “blood products”. How far down the supply chain does that classification apply? If I make cars, and one of my employees gets injured and needs a blood transfusion, are my cars now “blood products”? Anyway, here’s my best guess for the percentage of products in this middle category that use human blood: Category Description Needs blood (guess) Exports ($) Percentage of US goods exports 3002.13.00.00 IMMUNOLOGICAL PRODUCTS, UNMIXED, NOT PUT UP IN MEASURED DOSES OR IN FORMS OR PACKINGS FOR RETAIL SALE 8% 49,942,648 0.0024% 3002.14.00.00 IMMUNOLOGICAL PRODUCTS, MIXED, NOT PUT UP IN MEASURED DOSES OR IN FORMS OR PACKINGS FOR RETAIL SALE 8% 404,869,296 0.0198% 3002.15.01.00 IMMUNOLOGICAL PRODUCTS, PUT UP IN MEASURED DOSES OR IN FORMS OR PACKINGS FOR RETAIL SALE 8% 1,065,388,517 0.0521% 3002.41.00.00 VACCINES FOR HUMAN MEDICINE, NESOI 5% 388,034,787 0.0190% 3002.51.00.00 CELL THERAPY PRODUCTS 80% 476,770,408 0.0233% 3002.90.52 HUMAN BLOOD; ANIMAL BLOOD PREPARED FOR THERAPEUTIC, PROPHYLATIC OR DIAGNOSTIC USES; ANTISERA AND OTHER BLOOD FRACTIONS, ETC. NESOI 90% 822,913,704 0.0402% TOTAL (GUESSED BLOOD)   3,207,919,363 0.1569% So 0.5298% of goods exports almost certainly use blood, and my best guess is that another 0.1569% of exports also include blood, for a total of 0.6867%. Obviously, this is a rough cut. But I couldn’t find any other source that shows their work in any detail, so I hoped that by publishing this I could at least prod Cunningham’s law into action. Sorry for all the numbers.

Examples are good. Let’s start with some examples: We all need kidneys, or at least one kidney. Donating a kidney sucks, but having zero working kidneys really sucks. Paying people for kidneys would increase the number available, but it seems gross to pay people for part of their body. Donating a kidney is low-risk, but not zero risk. If you pay for kidneys, the extra kidneys tend to come from poorer people. So we don’t pay, and every day people die for lack of a kidney. Except for Iran. Yes, in Iran you can legally buy or sell a kidney for a few thousand dollars. There is no waiting list for transplants, but most sellers seem driven by desperation and overall it doesn’t sound super awesome. We all need a heart. Paying someone for their heart would mean paying for suicide. If we were to auction off hearts from organ donors, they would tend to go to rich people. People die every day from lack of a heart, but you don’t hear much about trading hearts for money. Many people need blood plasma. For some people (me) donating blood plasma is a psychological nightmare. For other people it’s fine. Not getting plasma when you need it is very bad. Paying people for plasma means more plasma, mostly from low-income people. Much of Europe has long prohibited paying for plasma. Denmark and Italy met their needs with altruistic donors (Edit: Incorrect, Thanks to The Plasma Professor), but overall Europe had a shortage of around 38%, which it met by importing plasma from paid donors in the United States, where blood products account for 2% 0.7% of all (goods) exports by value. The EU recently legalized limited payments for blood donations. The French government opposed this change. The French government owns a company that runs paid plasma centers in the United States. Some people want hair. Prohibiting people from selling their hair is stupid. You should be allowed to sell your hair. We all need a liver. You can—amazingly—give away half your liver and re-grow the rest in a few months. This is pretty safe, but compared to donating a kidney is a more complex surgery with a longer recovery period and 3-10× the mortality risk. Steve Jobs got pancreatic cancer in 2003. This was a rare form that often responds to treatment, but Jobs initially refused surgery and spent almost a year doing “alternative” treatments. Finally in 2004 he had surgery. In 2009, he had a liver transplant. This may have been needed as a consequence of Jobs’ decision to delay treatment in 2003. Tim Cook offered half his liver, but Jobs angrily refused. Most people in this situation would not have been eligible for a liver from the public donor registry, but Jobs was able to leverage his wealth and connections to both get classified as eligible and jump the queue. Jobs died two years later. We all need food. Food that is healthier or tastier is often more expensive. Rich people get to eat more of it. Our for-profit food production system is really efficient and in rich countries the main problem is eating too much food. We all need somewhere to live. Housing that is closer to high-paying jobs or larger/nicer is more expensive. Richer people get to live in nicer homes. The cost of housing means many people need to accept long commutes or live with lots of roommates or cities with worse job opportunities. Buildings needs roofs. In North America, roofs are most often made of asphalt shingles, which need to be replaced every 10-30 years. Roofing work is exhausting and miserable and dangerous. People would rather not do roofing. Roofing is well-paid given the qualifications. We have the technology to make roofs that last for 100 years, at a lower long-term cost. Nobody suggests making it illegal to pay people to do roofing. Large pink diamonds are rare. Only rich people get to have large pink diamonds. This is fine. If there’s a sudden shortage of fuel, then you can either ration or let prices go up. If you let prices go up, then rich people get to drive more, but if you need fuel to drive grandma to the hospital, you can buy some. Cars need to park. If there’s a shortage of parking, you can either raise prices or let people fight for spots. If you raise prices, then rich people get to park more, but if you need to park next to the hospital to drop off grandma, you can do so. If you don’t raise prices, people drive around endlessly looking for spots, wasting energy, creating pollution, and slowing traffic. We all want to buy goods and services. People sell these to us for money. They do that because they can use the money to buy other stuff they want. If money didn’t provide any advantage, they wouldn’t do that. Many people want babies. The idea of auctioning off babies is gross. Nobody wants to auction off babies. Many people want babies, but can’t biologically carry a baby to term. Carrying a baby to term is hard on your body and deeply personal. In much of the world, it’s illegal to have someone else to do this for you. In most of the rest, it’s illegal to pay someone to do it. In a few places it’s legal to pay. (Contemplate this list: Arkansas, Belarus, California, Florida, Illinois, Kazakhstan, Maine, Nevada, New Hampshire, Russia, Ukraine, Vermont, Washington.) The people who purchase this service are usually richer than the women they buy it from. If you’re willing to pay a woman to be a surrogate, some third party might coerce her and steal the money. People who live in places where commercial surrogacy is illegal often buy it from places where it’s legal. Most adults want sex. Some have difficulty accessing it. Paying for sex increases the supply of sex. Some people believe paid sex is degrading or has harmful cultural effects. If you’re willing to pay someone for sex, some third party might coerce them and steal the money. Paying for sex is illegal in most of the world. In places where it’s legal, organized brothels are often illegal. In a few places (Canada, France, Ireland, Norway, Sweden) it’s legal to sell sex but not buy it. Sometimes on planes I think about offering the person in front of me some money to not recline their seat. I don’t do this because I’m pretty sure it would end with them either (A) refusing and thinking I’m a huge jerk or (B) doing it for free and thinking I’m a huge jerk. Lots of people want to move to rich countries. Some rich countries let people based on employment, some based on family, and some on “points”. If you auctioned off the right to move to a rich country, you’d get a mixture of people who (A) have lots of money, and (B) would economically benefit from moving. A few places—including arguably the United States—do this already. Lots of people want their kids to get better grades. Lots of people pay for tutors or extra after-school education. You could directly pay your kids to get good grades. This seems strange and possibly bad, though I’m not sure why. OK, but how do you feel? After working through these kinds of cases, I feel: Squishy. I’m attracted to simple rules that can rise to tame the complexity of the real world. But the more I think about these cases, the less optimistic I feel about such rules. Like every rationalist-adjacent blogger, I lean vaguely libertarian and consequentialist. (I wish I was more unique and interesting.) So I sometimes find myself thinking in high-handed slogans. Things like, “The government should not intrude in arrangements between consenting adults”, or “The right policy is whatever makes the outcome as good as possible.” I like how those words sound. But are they actually useful? For example: Paid sex is not my thing. But there are some scenarios (e.g. people with certain disabilities) where prohibiting it seems downright cruel and providing this service downright noble. On the other hand, when you talk about “arrangements between consenting adults”, it seems to call to mind a sort of theoretical idealized society. Like most people, I like to blithely imagine the Netherlands are such a society. After formally legalizing sex work in 2000, they’ve been creative and tenacious in trying to address organized crime and coercion. It sounds like it’s going OK, but not exactly great? I guess almost every other country has lower state capacity and would do somewhat worse. Or take kidneys again. Say we had a total free market libertarian utopia/dystopia: If a rich person wants a kidney, they can go find a drug addict, hustle them into a clinic, get them to sign some forms, hand them some cash, and then take their kidney. That sounds gross. I’m not 100% confident I could win a debate arguing from first-principles that it’s grosser than our current system in which thousands of people die every year for lack of a kidney. But I’m not too worried about that, because it has zero chance of happening. The Coalition to modify the National Organ Transplant Act wants to pay people to donate kidneys. They suggest a months-long screening process that only the 10% of people at lowest risk would pass. Donors would get no money up front, but would get $10,000 per year when they file their taxes for the next five years. This seems less gross than the libertarian {u,dys}topia because people couldn’t donate if they were high risk, because there’s a long waiting period, and because the resulting kidneys would be given out according to the current (non-market) system based on need and potential benefit. The Coalition points also out that lower-income people would benefit the most from extra kidneys, since rich people tend to have healthy friends and family who are willing and able to give a directed donation. They also point out that the lowest-income people are the least likely to qualify as low-risk donors. But common sense still says the extra donors you get by paying people will tend to be lower income. I don’t love that. But I think it’s silly to look at the flaws of one system without comparing to the flaws of the alternatives. As far as I can tell, those are: (1) Do nothing and let thousands of people continue to die every year. (2) Pay rich people extra when they donate. (3) Force everyone to register for some kind of kidney donation “lottery”. (4) Reeducation campaigns. (5) Marxism. Maybe the Coalition’s proposal is the “worst system other than all the other systems”. In both cases (paid sex and paid kidneys) rules and slogans are weak. The action is in details. The grossness spectrum What makes some things seem grosser than others? There seem to be many factors. Do some people need the stuff more than others? Will trading for money get the stuff to the people who need it more? Will money increase production? Do we want more production? Here’s a case I find particularly confounding: Why does paying a surrogate mother seem not-that-bad (at worst), but auctioning off a baby seem horrific? Sure, surrogate mothers usually use genetic material from the clients, but even with an embryo from third parties, it still seems OK. Yet, if I buy an embryo and then pay a surrogate mother, haven’t I just bought a baby in advance? I can’t find any clear distinction, but I also can’t get myself to bite the bullet and say the two are equivalent. But I do have one theory. In terms of how gross it is to sell body parts like normal market products, I think everyone agrees the order is hair < blood ≪ kidney < liver ≪ heart. I don’t think that order is controversial. The main way people differ is in terms of where they’d draw the line. As you’ve surely surmised, I lean somewhere right of “kidney”. While this is a minority view in the world, I suspect it’s a majority view among people reading this. So I thought I should make the case for drawing the line near the left end of the spectrum. Here goes: When I picture paying someone for a kidney, I picture someone who is healthy and hearty. They’re thriving in life and don’t need money, but they drive a Honda and they really want an Acura, so they sell a kidney and buy an Acura and live happily ever after. When I think of paid surrogates, I picture a woman who loves being pregnant so much she’d almost do it for fun. Lovely. But in the existing organ industry in Iran sounds grim. Many sellers seem motivated by extreme poverty and financial desperation. If someone does something out of desperation, you can argue that—almost by definition—this means it helps them, and removing the option would hurt them. But suppose that if everyone had their basic needs met, then almost no one would donate their kidneys for money. Then you can argue that paying for kidneys is a step in the wrong direction. We should be moving towards a society where no one is desperate and people donate out of altruism. Paying for donations calcifies the current systems and papers over our problems instead of correcting them. I don’t really agree, because I like incremental progress and I’m allergic to anything that verges on “the worse the better”. But I see where it’s coming from.

I don’t know how to internet, but I know you’re supposed to get into beefs. In the nearly five years this blog has existed, the closest I’ve come was once politely asking Slime Mold Time Mold, “Hello, would you like to have a beef?” They said, “That sounds great but we’re really busy right now, sorry.” Beefing is a funny thing. Before we invented police and laws as courts, gossip was the only method human beings had to enforce the social compact. So we’re naturally drawn to beefs. And, as I’ve written before, I believe that even with laws and courts, social punishment remains necessary in many circumstances. The legal system is designed to supplement social norms, not replace them. Beefs tend to get a lot of attention. I like attention. I hope I get credit when the world inevitably turns against ultrasonic humidifiers. But I don’t really want attention for beefing. I don’t have a “mission” for this blog, but if I did, it would be to slightly increase the space in which people are calm and respectful and care about getting the facts right. I think we need more of this, and I’m worried that society is devolving into “trench warfare” where facts are just tools to be used when convenient for your political coalition, and everyone assumes everyone is distorting everything, all the time. Nevertheless, I hereby beef with Crémieux. That’s the start of a recent thread from Crémieux on the left, and sections from a post I wrote in 2022 on the right. Click here if you want to see the tedious details for the rest of the thread. Is this plagiarism? I think so. And I don’t think it’s a close call. Plagiarism is: Presenting work or ideas from another source as your own, with or without consent of the original author, by incorporating it into your work without full acknowledgement. And in particular: Paraphrasing the work of others by altering a few words and changing their order, or by closely following the structure of their argument, is plagiarism if you do not give due acknowledgement to the author whose work you are using. A passing reference to the original author in your own text may not be enough; you must ensure that you do not create the misleading impression that the paraphrased wording or the sequence of ideas are entirely your own. Applying this definition requires some judgement. Crémieux took eleven (unattributed) screenshots from my posts, as well as the entire structure of ideas. But there was a link at the end. Would it be clear to readers where all the ideas came from? Is the link at the end “due acknowledgement”? I think few reasonable people would say yes. There are also several phrases and sentences that are taken verbatim or almost verbatim. E.g. I wrote: Aspartame is a weird synthetic molecule that’s 200 times sweeter than sucrose. Half of the world’s aspartame is made by Ajinomoto of Tokyo—the same company that first brought us MSG back in 1909. And Crémieux wrote: Aspartame is a sugary sweet synthetic molecule that’s 200 times sweeter than sucrose. More than half of the world’s supply comes from Ajinomoto of Tokyo, better known for bringing the world MSG. This does not happen by accident. Crémieux seemed to understand this when former Harvard president Claudine Gay was accused of plagiarism. But I still consider this something of a technicality. It happens that Crémieux got sloppy and didn’t rephrase some stuff. But you could easily use AI to rephrase more and it would still be plagiarism. Why complain? I don’t understand twitter. Maybe this is normal there. But I understand rationalist-adjacent blogs. If this was some random person, I’d probably let it go. But Crémieux presents as a member of my community. And inside that community, I feel comfortable saying this is Not Done. And if it is done, I expect an apology and a correction, rather than a long series of suspiciously practiced deflections. I don’t expect this post will do much for my reputation. When I read it, I feel like I’m being a bit petty, and I should be spending my time on all the important things happening in the world. I think that’s what Crémieux is counting on: There’s no way to protest this behavior without hurting yourself in the process. But I’ve read Schelling, and I’m not going to play the game on that level. I’d like to be known as a blogger with a quiet little community that calmly argues about control variables and GLP-1 trials and the hard problem of consciousness, not someone who whines about getting enough credit. But I’ve decided to take the reputational hit, because norms are important, and if you care about something, you have to be willing to defend it.

Theanine is an amino acid that occurs naturally in tea. Many people take it as a supplement for stress or anxiety. It’s mechanistically plausible, but the scientific literature hasn’t been able to find much of a benefit. So I ran a 16-month blinded self-experiment in the hopes of showing it worked. It did not work. At the end of the post, I put out a challenge: If you think theanine, prove it. Run a blinded self-experiment. After all, if it works, then what are you afraid of? Well, it turns out that Luis Costigan had already run a self-experiment. Here was his protocol: Each morning, take 200 mg theanine or placebo (blinded) along with a small iced coffee. Wait 90 minutes. Record anxiety on a subjective scale of 0-10. He repeated this for 20 days. His mean anxiety after theanine was 4.2 and after placebo it was 5.0. A simple Bayesian analysis said there was an 82.6% chance theanine reduced anxiety. The p-value was 0.31, but this is a Bayesian blog—this is what you'd expect with a sample size of 20. A sample size of 20 just doesn’t have enough statistical power to have a good chance of finding a statistically significant result. If you assume the mean under placebo is 5.0, the mean under theanine is 4.2, and the standard deviation is 2.0, then you’d only have a 22.6% chance of getting a result with p<0.05. I think this experiment was good, both the experiment and the analysis. It doesn’t prove theanine works, but it was enough to make me wonder: Maybe theanine does work, but I somehow failed to bring out the effect? What would give theanine the best possible chance of working? Theanine is widely reported to help with anxiety from caffeine. While I didn’t explicitly take caffeine as part of my previous experiment, I drink tea almost every day, so I figured that if theanine helps, it should have shown up. But most people (and Luis) take theanine with coffee, not tea. I find that coffee makes me much more nervous than tea. For this reason, I sort of hate coffee and rarely drink it. Maybe the tiny amounts of natural theanine in tea masked the effects of the supplements? Or maybe you need to take theanine and caffeine at the same time? Or maybe for some strange reason theanine works for coffee (or coffee-tier anxiety) but not tea? So fine. To hell with my mental health. I decided to take theanine (or placebo) together with coffee on an empty stomach first thing in the day. And I decided to double the dose of theanine from 200 mg to 400 mg. Details Coffee. I used one of those pod machines which are incredibly uncool but presumably deliver a consistent amount of caffeine. Measurements. Each day I recorded my stress levels on a subjective 1-5 scale before I took the capsules. An hour later, I recorded my end stress levels, and my percentage prediction that what I took was actually theanine. Blinding. I have capsules that either contain 200 mg of theanine or 25 mcg of vitamin D. These are exactly the same size. I struggled for a while to see how to take two pills of the same type while being blind to the results. In the end, I put two pills of each type in identical looking cups and shuffled the cups. Then I shut my eyes, took a sip of coffee (to make sure I couldn’t taste any difference), swallowed the pills on one cup, and put the others into a numbered envelope. Here’s a picture of the envelopes, to prove I actually did this and/or invite sympathy for all the coffee I had to endure: After 37 days I ran out of capsules. Initial thoughts I’m going to try something new. As I write these words, I have not yet opened the envelopes, so I don’t know the results. I’m going to register some thoughts. My main thought is: I have no idea what the results will show. It really felt like on some days I got the normal spike of anxiety I expect from coffee and on other days it was almost completely gone. But in my previous experiment I often felt the same thing and was proven wrong. It wouldn’t surprise me if the results show a strong effect, or if it’s all completely random. I’ll also pre-register (sort of) the statistical analyses I intend to do: I’ll plot the data. I’ll repeat Luis’s Bayesian analysis, which looks at end stress levels only. I’ll repeat that again, but looking at the change in stress levels. I’ll repeat that again, but looking at my percentage prediction that what I actually took was theanine vs. placebo. I’ll compute regular-old confidence intervals and p-values for end stress, change in stress, and my percentage prediction that what I actually took was theanine vs. placebo. Intermission Please hold while I open all the envelopes and do the analyses. Here’s a painting. Plots Here are the raw stress levels. Each line line shows one trial, with the start marked with a small horizontal bar. Remember, this measures the effect of coffee and the supplement. So even though stress tends to go up, this would still show a benefit if it went up less with theanine. Here is the difference in stress levels. If Δ Stress is negative, that means stress went down. Here are the start vs. end stress levels, ignoring time. The dotted line shows equal stress levels, so anything below that line means stress went down. And finally, here are my percentage predictions of if what I had taken was actually theanine: So…. nothing jumps out so far. Analysis So I did the analysis in my pre-registered plan above. In the process, I realized I wanted to show some extra stuff. It’s all simple and I think unobjectionable. But if you’re the kind of paranoid person who only trusts pre-registered things, I love and respect you and I will mark those with “✔️”. End stress The first thing we’ll look at is the final stress levels, one hour after taking theanine or vitamin D. First up, regular-old frequentist statistics. Variable Mean 95% C.I. p theanine end stress 1.93 (1.80, 2.06)   vitamin D end stress 2.01 (1.91, 2.10)   ✔️ difference (T-D) -0.069 (-0.23, 0.083) 0.33 If the difference is less than zero, that would suggest theanine was better. It looks like there might be a small difference, but it’s nowhere near statistically significant. Next up, Bayes! In this analysis, there are latent variables for the mean and standard deviation of end stress (after one hour) with theanine and also for vitamin D. Following Luis’s analysis, these each have a Gaussian prior with a mean and standard deviation based on the overall mean in the data. Variable Mean 95% C.I. P[T better] end stress (T) 1.93 (1.81, 2.06)   end stress (D) 2.00 (1.91, 2.10)   difference (T-D) -0.069 (-0.23, 0.09) 80.5% ✔️ % diff (T-D)/D -3.38% (-11.1%, 4.71%) 80.5% The results are extremely similar to the frequentist analysis. This says there’s an 80% chance theanine is better. Δ Stress Next up, let’s look at the difference in stress levels defined as Δ = (end - start). Since this measures an increase in stress, we’d like it to be as small as possible. So again, if the difference is negative, that would suggest theanine is better. Here are the good-old frequentist statistics. Variable Mean 95% C.I. p theanine Δ stress 0.082 (-0.045, 0.209)   vitamin D Δ stress 0.085 (-0.024, 0.194)   ✔️ difference (T-D) 0.0026 (-0.158, 0.163) 0.334 And here’s the Bayesian analysis. It’s just like the first one except we have latent variables for the difference in stress levels (end-start). If the difference of that difference was less than zero, that would again suggest theanine was better. Variable Mean 95% C.I. P[T better] Δ stress (T) 0.0837 (-0.039, 0.20)   Δ stress (D) 0.0845 (-0.024, 0.19)   difference (T-D) -0.0008 (-0.16, 0.16) 50.5% ✔️ % diff (T-D)/D 22.0% (-625%, 755%) 55.9% In retrospect, this percentage prediction analysis is crazy, and I suggest you ignore it. The issue is that even though Δ stress is usually positive (coffee bad) it’s near zero and can be negative. Computing (T-D)/D when D can be negative is stupid and I think makes the whole calculation meaningless. I regret pre-registering this. The absolute difference is fine. It’s very close (almost suspiciously close) to zero. Percentage prediction Finally, let’s look at my percentage prediction that what I took was theanine. It really felt like I could detect a difference. But could I? Here we’d hope that I’d give a higher prediction that I’d taken theanine when I’d actually taken theanine. So a positive difference would suggest theanine is better, or at least different. Variable Mean 95% C.I. p % with theanine 52.8% (45.8%, 59.9%)   % with vitamin D 49.3% (43.2%, 55.4%)   ✔️ difference (T-D) 3.5% (-5.4%, 12.4%) 0.428 And here’s the corresponding Bayesian analysis. This is just like the first two, except with latent variables for my percentage prediction under theanine and vitamin D. Variable Mean 95% C.I. P[T better] % prediction (T) 52.7% (45.8%, 59.6%)   % prediction (D) 49.3% (43.4%, 55.2%)   difference (T-D) 3.3% (-5.7%, 12.4%) 77.1% ✔️ % diff (T-D)/D 7.2% (-10.8%, 27.6%) 77.1% Taking a percentage difference of a quantity that is itself a percentage difference is really weird, but fine. Discussion This is the most annoying possible outcome. A clear effect would have made me happy. Clear evidence of no effect would also have made me happy. Instead, some analyses say there might be a small effect, and others suggest nothing. Ugh. But I’ll say this: If there is any effect, it’s small. I know many people say theanine is life-changing, and I know why: It’s insanely easy to fool yourself. Even after running a previous 18-month trial and finding no effect, I still often felt like I could feel the effects in this experiment. I still thought I might open up all the envelopes and find that I had been under-confident in my guesses. Instead, I barely did better than chance. So I maintain my previous rule. If you claim that theanine has huge effects for you, blind experiment or GTFO.