Jens 'n' Frens
Idle thoughts of a relatively libertarian Republican in Cambridge, MA, and whomever he invites. Mostly political.
"A strong conviction that something must be done is the parent of many bad measures."
-- Daniel Webster
Thursday, September 09, 2021 :::
Some miscellaneous thoughts related to herd immunity, especially as it relates to covid.
- Until at least 18 months ago, the term "herd immunity" was pretty much always used in the context of vaccination, wasn't it? "We need enough people vaccinated against measles to get to herd immunity." More recently you have to attentive to context, and, where context is lacking, try to figure out whether the speaker means something else; a lot of people now seem to refer to "herd immunity" as opposed to vaccination, i.e. enough people get infection and natural acquired immunity that we get to herd immunity that way. Of course, both contribute, though in a highly vaccinated regime as we've had for measles in the last fifty years, especially the last quarter of the twentieth century, there's little natural acquaired immunity because the disease can't really spread, which of course is the point.
- At some point last year some folks were advocating for just trying to seal off the most vulnerable populations and letting covid rip through the less vulnerable populations, and this was much maligned; probably too much. The likelihood that a vaccine would become available seemed to me like a crucial part of the counterargument; in particular, suppose there would be no vaccine possible, and assume away evolutionary dynamics --- I have a response to them, but verbalizing it requires more work than I want to do here. If that's the case, then, once elimination has been ruled out as a possibility, if we're ever going back to normal, it's going to be through herd immunity; if the basic reproduction number is 3, 2/3 of the population will get the disease, and controls just postpone things somewhat. Now, if hospital capacity constraints are an issue, you want to delay things enough to respect that, but ultimately, if 2/3 of the population is going to get infected, to the extent that you can choose which 2/3 that is, it seems that you want to choose the 2/3 who are least "vulnerable" and get them infected --- preferably as soon as possible, so that you can get back to "normal" quickly and because your ability to isolate the vulnerable people is going to be limited, and probably better the less the time you have to sustain it.
- The term "endemic" seems a bit fuzzy; at least in theory, I conceive of it as the end phase in which the fraction of the population that has been infected is more or less stationary. Typically this means that, if that fraction is about 80%, the rate of newly infected people is about 80% of the birth rate. Even with an endemic disease, though, you don't expect exact stationarity; you'll get little outbreaks in various places, and there will be seasonal fluctuations, so on a broad scale at least the fraction probably bobbles up and down a bit. As a practical issue, though, things are even a bit harder, because we can't really measure the fraction of actual infections, let alone tell whether a plateau or slight dip is herd immunity or a pause before the next leg higher. A lot of people seem to use the term in a way that is basically sociological; a disease is endemic when a society has basically decided to treat it the way that that society treats endemic diseases. There perhaps should be a different definition as well, but the sociological one may ultimately be just as important.
::: posted by dWj at 10:55 AM
Monday, August 16, 2021 :::
I'm writing this on a morning on which nobody believes the withdrawal of US forces from Afghanistan was executed well, and some of the opponents of withdrawal are stealing some bases. I consider both pro-withdrawal and anti-withdrawal to be reasonable, arguable positions, and I don't intend here to be arguing against withdrawal per se, but I'm arguing against a particular argument for it.
For the last few years, our deployment to Afghanistan was small, and the number of casualties very low. That seemed to be sufficient to hold things stable in terms of denying terrorists most of the country, protecting most of its citizens from their depravities, sustaining for the United States military and intelligence an outpost in an important part of the world, and so on. Let's suppose that leaving that contingent in place for another three months would bring us those benefits for another three months, with no other changes in the situation; we then should ask whether those benefits are worth those costs. What I often see instead is people seeming to argue that these costs count as costs, but these benefits don't count as benefits, and that the only reason to keep any presence there is if it can buy us benefits that are longer lasting than the costs.
This has the feel of the idiotic but pervasive framing of renting a house as "throwing money away", which gets the whole housing thing exactly backward. Indeed, the complication with any investment, including housing (or "residential fixed investment", as it is called in the national accounts), is that you have to compare a "stock" — a cost incurred "at once", or in practice over a short period of time — with a "flow", the continued benefit from it over a long period of time. Buying a house presents this trickier problem, where renting does not; the running benefit can be matched up with the running cost. Indeed, a useful way to think of buying a house is to imagine that you are prepaying that portion of the future rents that would not go to running expenses, e.g. maintenance, insurance, and property taxes. If you buy a house, I encourage you to estimate the future rent you are effectively paying, perhaps using the (somewhat-recently paywalled) New York Times renting-versus-buying calculator; if you put in reasonable assumptions, the effective rent will certainly be positive, and will typically be comparable to the rents of similar housing.
There are certainly times — in foreign policy and adjacent fields as anywhere else — when stocks have to be compared to flows. To the extent the premises I presented are correct, this isn't one of those times; we have the simpler choice of comparing flows with flows. What would we buy by having troops there for another five years? We would buy another five years of the status quo. How long should we leave the troops there? For as long as it offers a higher benefit than the cost.
Now, I do suspect that something would change over time, and indeed that having troops there would effect some kind of change, though I don't know whether that would be good or bad. I'm more inclined than I was a month ago to think that the cost of maintaining the status quo would have gone up if the Taliban hadn't anticipated our departure at some point soon. There is probably some change in stock that needs to be taken into account here. What I find remarkable, and frustrating, is the denial of what seems to me to be the more obvious part of the equation: the primary benefit was the ongoing benefit, which was substantial.
 One reason to buy (or rent) rather than rent (or buy) may well be that different kinds of housing are often available; in may places rental housing is primarily apartments and resident-owned housing is primarily single-family. Usually there are enough single-family homes for rent for at least some notion of what the rental rates are to exist.
 Sometimes you will get lucky, or perhaps have special local knowledge, and, even after accounting for your labor costs in doing any DIY projects, the house price will rise fast enough after the fact for your rent to be, ex post, lower than you expected; sometimes you will get unlucky, as I did with my first home purchase and my parents did with theirs. Neither is to be counted on.
::: posted by dWj at 11:09 AM
Sunday, June 13, 2021 :::
This post was going to start with a discussion of prescriptivism versus descriptivism and semantics in general, but that's a different essay (which I intend to write, but not soon) and felt like throat-clearing in this context. Today I want to note a few words that I see used in ways that lack a nuance that I think the words ought, in some sense, to have. I'm not a hard-core adherent to the Sapir-Whorf hypothesis, but I worry that people using these words too generally in some cases inculcate the conflation of importantly different ideas. (Perhaps ironically, in two of the cases I will treat verb and noun forms of the words together, not really bothering to distinguish between them.)
- I don't recall, before a few years ago, seeing constructions like "both teams played each other today", but these days I occasionally do, and it sounds wrong to me. "Both" implies a parallelism, rather than a mutualism; if, speaking of Thing 1 and Thing 2, you can say "both of them [X]" for some verb [X], it is like saying "Thing 1 [X], and also Thing 2 [X]". I don't know whether there are native speakers of American English who disagree with me, but when I see the "mutualism" use of "both" I tend to imagine it's someone who learned English as a second language. While this use sounds wrong and annoying, though, I don't think the distinction it obscures is as important as in the other cases I'm mentioning in this post.
- The word "hoard" derives from a middle English word applying only to dragons and gold, which you haven't heard before because I just made it up. I do believe it generally evokes something like a dragon sitting on a pile of gold, and more generally a situation with two key features: 1) whatever is in being hoarded is not being used; it is just sitting there, and 2) what is being hoarded has been pulled out of circulation of a more-or-less fixed stock. If the best football teams recruit players who are pretty good, but not good enough to make their own team, especially with the intention of keeping them off of opposing teams, that looks like "hoarding" to me. If the players are going to get substantial playing time, that's not hoarding. If a collection consists of things that the owner itself produced, it ipso facto lacks the second characteristic of hoarding; in the case of a football team, if the players it recruits aren't a lot better than players other teams recruit, but it's a lot better at player development, it similarly is not "hoarding" good players. I think this is an important distinction: not all collections, or even large collections, are "hoards"; "hoard" implies something importantly different.
- I, like many other people, jocularly use the word "bribe" to refer to situations in which I provide some incentive to my child to do something, particularly something he in some sense "should" do on his own. It's worth keeping in mind, though, that an "actual" bribe involves inducing someone to violate a duty of some sort to a third party, typically one for which the bribee is acting as an agent. I occasionally see the word used to disparage voluntary exchange that deserves no disparagement, and certainly not for inducement to violate a fiduciary duty.
The following two words are different from the preceding three, in that I don't believe that the words do make a distinction when used as I perceive "correctly", but I want to note that they take in very diverse concepts that deserve a distinction, with the same Sapir-Whorf risks of conflation.
- You may believe it rare, and you may believe it should be illegal, but creating a market between voluntary sellers and buyers of sex is a quite different activity from holding someone as a sex slave to be rented out.
- A prospective mother choosing her sperm donor on the basis of perceived superiority of genetic stock is worlds different from forcibly sterilizing "imbiciles". The word "eugenics" often seems to be pulled out in contexts closer to the former to intentionally conflate them with the latter; somehow when "eugenics" went out of vogue some of the opprobrium justly attached to state violations of human rights, which should have gotten stuck to other state violations of human rights, instead got stuck to other kinds of "eugenics".
::: posted by dWj at 2:14 PM
Thursday, April 01, 2021 :::
Suppose that it is agreed that it is within the proper authority of government under current circumstances to place substantial restrictions on people in order to curb the contagion of disease. The purpose isn't --- or certainly shouldn't be --- to torment people, to destroy society, to ruin businesses. The purpose should be to curb contagion and, in particular, hospitalizations and death. Accordingly, if there are large classes of activities that present very low risk of creating contagion, those should be allowed. I think historically the cultural right in particular has recognized arguments like "it's not fair that you're clamping down on high-cost activities but not low-cost activities" as nonsense; indeed, clamping down on low-cost activities in the name of "fairness" is closer to petty vindictiveness than it is to fairness.
This is true of activities, but is also true of people, and there some things do get trickier. When a couple of people come into the country with ebola, we isolate those people, while everyone else largely goes about their business. It makes no sense to restrict people who are known not to be carriers of any disease; what is trickier is when we don't know who is spreading the disease. A fuller test-and-trace system would have allowed better-targeted restrictions; if you can restrict 5% of the population and thereby 90% of carriers of the disease you have to do little else to keep the infection rate down. Perhaps test-and-trace would have worked better with higher state capacity, but I have the impression there was also a fair amount of resistance to it by a lot of the population that was worried about privacy. I feel like we've given up a lot more private control of our lives than we would have if test-and-trace had been effective.
So now we get to talk about "vaccine passports". Some people arguing for a vaccine passport system talk actively as though they want to punish people who choose not to get the vaccine; many more people argue for it as an incentive for people to get the vaccine, which seems less execrable but still to the side of the main point. As evidence accrues that people who are fully vaccinated spread the disease far less than people who aren't, it is simply the case that, at certain levels of case counts, some activities are quite risky (to themselves but also to others) when carried out by some people than when carried out by others. If there are restrictions that make sense, but are unnecessary for people who are vaccinated, it makes sense to make that discrimination.
I have heard a suggestion that it is too early to talk about vaccine passports; this assertion seems to come from the idea that the sole purpose of the passports is to incentivize getting vaccinated, and the observation that demand still exceeds supply. In fact, because I reject that as a particularly good motive for vaccine passports, I think the window of time in which they make sense is in fact likely to close within a couple of months; once case numbers nationally are down below 10,000 per day, things should basically be open regardless of who has been vaccinated, and I'm hopeful that herd immunity will get us there by the end of the summer. The reason to be especially skeptical of vaccine passports now, then, is the permanence of government programs; especially if they are required by governments to engage in various activities, it seems optimistic to think that the restrictions (and privacy costs) will be as curtailed in time as they should be.
::: posted by dWj at 1:11 PM
Tuesday, May 05, 2020 :::
One of the skills I'm still working on is the ability to figure out what certain audiences will find obvious. I don't know, then, how much argumentation is in bad faith, ignoring what seem to me to be the obvious positions of people against whom the argumentation is being made; indeed, sometimes I worry that what seem to me like the obvious understanding of a viewpoint might actually be wrong after all. I'm going to, then, note here some things that I think are obvious, and that I tend to take for granted as obvious to all discussants, though they seem to be inconsistent with the assumption that people are arguing in good faith, which is an assumption I usually prefer to grant.
In some idealized world, it might be optimal for choices for higher levels of risk to come with compensation paid by the people who accrue greater benefits, are less exposed to risks, and are generally more risk-tolerant to the people who accrue fewer benefits, are more exposed to risks, and are more risk-averse, and for choices with lower levels of risk to come with transfers the other direction. Where that is impractical, I think we should make efforts to account for everyone in our choices and to suppose, in the absence of strong evidence to the contrary, to suppose that others are to some extent doing the same.
- Everyone takes actions voluntarily that trade a risk to their own life against some other value.
- It is reasonable for different people to make tradeoffs between safety and other values differently.
- When there's a pandemic on, it is much more than usually the case that one person's actions will affect the safety of many other people in a substantial way.
- In particular, note that if I can cut my exposure to people by 85%, while other people make choices that cause 10 times the local prevalence of the contagion, I am under a greater risk than the baseline. The assertion that people with different preferences can make different choices, which is true to any practical extent in many situations, is simply not true in this situation.
It is quite reasonable (and not selfish) for someone who would prefer greater risk (in exchange for other values) to advocate for us to collectively make choices with greater risk, just as
it is quite reasonable (and not selfish) for someone who would prefer less risk (at the expense of other values) to advocate for us to collectively choose a lesser level of risk.
The risks and benefits will fall differently on different populations; it would be polite for people who are likely to be more exposed to risks and to accrue less in benefits, and for people who are less exposed to risks and accrue more in benefits, to make some effort to respect the different situations of others.
::: posted by dWj at 4:26 PM
Wednesday, November 13, 2019 :::
Bitcoin is regarded as a digital currency, to some extent, but I often find it useful to think of blockchain as a system for indelibly publishing messages. In the case of bitcoin, these messages are largely of the form "I am taking the bitcoin I got from [provenance] and giving X of it to [bitcoin address] and Y of it to [other bitcoin address]", and as part of the system of maintaining the blockchain it is verified that the sender has bitcoin from that provenance in a quantity that is no less than X+Y.
Actually buying bitcoin involves, as do all transactions, two legs: you give someone dollars or euros or pizza, and they publish a message on the blockchain publicly relinquishing some bitcoin to you. There are exchanges that get together people who want to trade dollars for bitcoin and people who want to trade bitcoin for dollars. When a match is found, the dollars are conveyed in some usual dollar-conveyance manner, and a bitcoin conveyance is published on bitcoin's blockchain. I'm starting, though, to sort of envision a system in which the blockchain itself serves as the exchange.
Consider a blockchain on which the messages took the form of "I trade W units of asset A and X units of asset B, from [provenances], for Y units of asset C and Z units of asset D." The process of incorporating a new block of such messages into the blockchain would require verifying that the person submitting the message has at least W units of A and X of B from the stated provenances, and also verifying that the entire block gives up at least as much of every asset as it conveys. If there is a very small set of prices that clear the market, then calculating how to put such trades together into a valid block gets computationally hard if a lot of these bids are very close to worth zero, but if there aren't too many assets, and there are a fair number of orders that give up a nonnegligible amount of value for some set of market prices, it becomes practically tractable, and certainly sufficiently tractable to reasonably incorporate into the "proof of work" that is part of bitcoin mining.
There are two big technological barriers that occur to me: the simpler one is that there has to be a way to cancel an order that doesn't get executed. It seems to me that bitcoin must have a way to deal with this — that, if I publish "I give Sam 2 bitcoins" and it doesn't go through within a reasonable amount of time that there must be a way to withdraw it or for it to expire — but I don't know what it is. Probably the message should include some sort of timestamp and/or expiration time, along with a hash of the message that includes the expiration. An actual cancel may be impossible.
The other, perhaps bigger, issue, is how the assets get on the relevant blockchain in the first place. If the only messages convey bitcoin, and all bitcoin originate at some level of indirection from bitcoin mining, then you have a fully closed system, and it's all fine. I can really only trade things that are on the blockchain, and for this to be useful they have to be able to somehow get there.
One possibility goes back to an older idea I had, and one that I later came to be was largely Ripple's initial idea, which is essentially to let each person have an asset that they can create out of thin air, simply by being them. I can trade "Dean's dollars" in any quantity for anything I can persuade other people to sell me; the problem is just in getting them accepted.. The provenance is just me. Other people can then trade them as they will, once I have put them out there. Maybe some of my friends would be willing to accept a certain amount of Dean's dollars among themselves; widespread acceptance would probably only come to a few currencies issued by a few people who are in some sense trusted (perhaps trusted to back their currency at some ratio with some basket of off-blockchain asset). You could imagine State Street publishing a list of blockchain addresses it maintains in which it promises to keep the "currency" of each address linked to a corresponding ETF.
Update: I meant to post this on my "Dean's Dough" blog, and have just cross-posted it there, but I'll leave it here, too, at least for the time being.
::: posted by dWj at 1:02 PM
Tuesday, September 03, 2019 :::
I don't think I've mentioned this here, but I've been thinking about it for a long time, and who knows The recent hook is discussion of how much the men's national soccer team is paid and how much the women's team is paid. There are various statistics and counter-statistics, but I want to raise a question that seems to me to be obviously prior to most of the others, largely unaddressed, and quite non-obvious in terms of its answer: to what extent should a team's pay be determined by its success?
Economically, sports leagues are obviously in the entertainment business; those that persuade people to pay more to be entertained by them are presumably entitled to that extra money. College sports teams tend to become more popular when they do better (against the other teams that they play); there is also a (looser) cross-sectional correlation where-in teams that tend to do better are more popular than teams that don't. I believe this holds up largely in professional sports as well, though I'm less sure of it; I certainly have the impression that the Chicago Cubs, in the second half of the twentieth century, had more popularity (relative to other major league baseball teams) than on-field success.
Sports analytic attempts to value players almost always attend solely to the player's effect on the team's ability to win games; I can think of very few occasions when a player seems to have been hired or paid more for a more entertaining style of play (with likelihood of winning held constant). This may simply be my ignorance; I welcome any anecdotes people have, especially ones that don't involve anyone named Veeck.
Within league it seems likely that imposing an incentive structure focused on winning creates a more entertaining product league-wide. Sports analytics, again, tends to tease out how many dollars a win costs in a given league; those wins are constant-sum within the league. I haven't seen research that tries to predict the revenues of a league as a function of anything about the players' talents or actions, though this seems very much like the kind of research that could exist without my having come across it. I'd like to know, in particular, to the extent that you could attribute revenue generation for the league to different members of the league, how the pay to a team or its players depends on its own revenue generated, its on-field success, and the total league revenue.
Ultimately, in principle, it seems very likely to me that there's a setting in which a bad team that brings in little revenue directly, in a good league brining in a lot of revenue collectively, might be worth more than a good team bringing in more revenue directly but in a league that brings in comparatively little revenue collectively.
 In other words: why aren't all professional sports leagues WWF wrestling? or Why do NBA teams make more money than the Harlem Globetrotters?
 I know little about the NBA, and have the impression that there are people who find slam dunks entertaining and there are players who gratuitously perform them; perhaps they have a financial incentive to do so, or perhaps I'm misinformed. These aren't mutually exclusive, either.
::: posted by dWj at 1:35 PM