kxyvr (u/kxyvr) - Readit News

kxyvr commented on What's driving rising business costs? libertystreeteconomics.ne... · Posted by u/jnord

metaphor · 8 days ago

Appreciate the perspective.

> A not small number of the rural docs are foreign born and trained and they essentially work this crappy jobs until they have permanent residency and then they move to more desirable markets.

Not sure that I follow how "rural" necessarily begets "crappy" though. Is the working quality of life somehow that much worse, or is it the relative social isolation and/or lack of recreational options while off duty, or is it really just a case of urbanite out of their accustomed habitat?

kxyvr · 8 days ago

It's a combination of factors. Rural hospitals and clinics tend to be under-resourced with lack of equipment in buildings that aren't particularly nice. As far as small town, if you like it, great. However, people who are highly educated tend to like to be around others who are similarly educated and that's difficult to find in a rural town unless it's also a university town. There tends to be a lack of school options for their children and given how much they spent on their own education, they tend to prioritize this highly. There tends to be a lack of town infrastructure like good grocery stores, or theater, or museums, or other amenities. Docs also have their own medical needs and understand that those can't be met at small clinics, so they like to have access to good hospitals. Imagine intimately knowing all the ways something like childbirth can kill you and also knowing that there's not an appropriately trained surgeon in town. By the time one finishes their training, they're probably in their 30s and may want to find a partner. Options tend to be limited in small towns. On the darker side of things, foreign people are often not particularly welcomed in rural towns and this can be a particularly bitter experience for the foreign docs that are essentially forced to work there.

So, no, it's not just an urbanite out of their comfort zone. There's a whole host of issues. And, to be clear, we need people to work these jobs, but it's not particularly pleasant for a lot of them.

kxyvr commented on What's driving rising business costs? libertystreeteconomics.ne... · Posted by u/jnord

metaphor · 8 days ago

> There were 147 unfilled slots for pediatricians, 805 for family medicine, and 357 for internal medicine. They don't have the applicants; it's not the slots.

You lost me...from your cite[1]:

  | Specialty         | Positions | Applicants | Matches | App/Pos | Deficit |
  |-------------------|-----------|------------|---------|---------|---------|
  | Pediatrics        |     3,135 |      3,998 |   2,988 |    128% |    4.7% |
  | Family Medicine   |     5,357 |      7,337 |   4,552 |    137% |   15.0% |
  | Internal Medicine |    10,941 |     17,131 |  10,584 |    157% |    3.3% |

I'm curious what conditions merit a "match".

Aren't a lot of these shortages scattered around rural areas where young doctors really don't want to move to? I understand from a buddy who is currently in med school that there are all sorts of incentive carrots being deployed to attract doctors to these underserved communities.

[1] https://www.nrmp.org/wp-content/uploads/2025/05/Main_Match_R...

kxyvr · 8 days ago

There's a video as to how the match works here:

https://www.nrmp.org/intro-to-the-match/how-matching-algorit...

Basically, you interview at a bunch of programs and then rank them. The programs (hospitals) rank applicants and then the algorithm does its magic to "match" applicants to programs. Now, if one doesn't match with any of them, there's something called the scramble where a med student works with their program to match into a program somewhere in some specialty that has room. This is non-ideal, but can work out.

Generally speaking, the match algorithm is setup to guarantee all U.S. medical school graduates a match somewhere in something. In may not be what you want, but you will have a job. Then, preference is given to things like the island schools (affiliated medical schools in the Carribean, which are very expensive, but somewhat easier to get into), and then to other international medical schools. Somewhere in there are also foreign physicians who want to work in the U.S., but are forced to redo residency.

I don't know everything about how it works, but that's the general idea. To that end, I don't fully understand the stats you pulled from the reference. That doesn't mean they're not valid, but I don't know.

And, yes, often times, there are open slots at some program in the middle of nowhere. As much as there can be incentives such some debt relief by working in rural hospitals, the jobs are not a good fit for a lot (most) people. I mean, someone just worked extremely hard for 10 years or more and you want them to go live in a town of 10k people. It's not that it's not important, but you can't force people to do it and it takes a particular personality to be happy there. A lot of highly educated people want to live in urban centers with amenities. Not all, but probably most.

Places like Canada use their foreign docs to fill this rural gap. A not small number of the rural docs are foreign born and trained and they essentially work this crappy jobs until they have permanent residency and then they move to more desirable markets. It's a trade, I guess, but there's not a small amount of resentment about it.

kxyvr commented on What's driving rising business costs? libertystreeteconomics.ne... · Posted by u/jnord

nradov · 8 days ago

My statement above was correct. There are students who graduate from accredited medical schools with MD/DO degrees but don't get matched. Part of that is because some of them simply don't apply to programs that have extra openings. Medicare / Medicaid pay primary care physicians below market rates so students are naturally reluctant to pursue those specialties.

kxyvr · 8 days ago

If they don't match, they're allowed to scramble and move into one of those programs with open positions. If they don't choose to, that's on them, but it's still not a problem with number of residency slots.

I very much agree that pay is a barrier to entering specialties like family medicine. Though it depends on the market, I normally see family medicine at around $200k/year and that's not great if one needs to take something like $750k debt to get there along with eight years of training after a bachelors. If we want to fix that, then we need to make the value proposition better and reduce the medical school debt, improve working conditions, and/or increase pay.

So, yes, if one wants to maximize their earning potential, then they need to enter one of the specialty residencies and fellowships. Those are currently filled. However, that's not where the biggest need is and I contend that's not why there's a physician shortage.

kxyvr commented on What's driving rising business costs? libertystreeteconomics.ne... · Posted by u/jnord

nradov · 8 days ago

The shortage of physicians has nothing to do with medical schools. The immediate bottleneck is a shortage of residency slots. Every year, students graduate from medical schools but are unable to practice medicine because they don't get matched to a residency program. (Some do get matched the following year.) This is primarily due to limited funding from Medicare, although some residency slots are funded from other sources.

https://savegme.org/

I agree that certificate of need laws should be repealed to increase competition between healthcare facilities. That only impacts some states, not the whole country.

https://nashp.org/state-tracker/50-state-scan-of-state-certi...

kxyvr · 8 days ago

That's not true. You can look at the residency match for 2025 here:

https://www.nrmp.org/match-data/2025/05/results-and-data-202...

While many specialties are fully filled, we need pediatricians, family medicine, and internal medicine docs. They're generalists and where the largest shortage is. There were 147 unfilled slots for pediatricians, 805 for family medicine, and 357 for internal medicine. They don't have the applicants; it's not the slots.

kxyvr commented on What's driving rising business costs? libertystreeteconomics.ne... · Posted by u/jnord

labcomputer · 8 days ago

The dirty little not-so-secret is that we pay doctors too much in the US. To the tune of several times as much as other large developed countries, like Germany, France and England. Medical care in the US will never ever be as cheap as those countries as long as the providers here earn 2x or 3x.

That's partly because we have a doctor shortage here (medical schools collude to limit the number of new doctors created each year).

Another part of the problem is the bloated administrative bureaucracy of hospitals in the US, we well as the fact that you aren't allowed to build a new hospital (and yes, this is actually true) unless you can prove that a hospital is needed in a particular community.

With no competitive market for healthcare providers, nor a competitive market for places where they work, why shouldn't they extract as much as they can from the rest of us?

They get away with it, too, because "medical doctor" is one of the highest trusted and most reputable professions. It's badthink to discuss these things in polite company.

Until we fix those things, it simply doesn't matter how the insurance/payment system works. Every time I hear that we need to get rid of private insurers, nobody can seem to explain how doing that will save more than 10-15% despite the fact that insurance companies have a statutorily-limited profit margin.

kxyvr · 8 days ago

No, they are not paid too much. There's a lot of incorrect assertions here, so it'll take a lot to work through them.

Physician pay depends on specialty, but it can range from the low $100kish mark for pediatricians to $500-750k for certain kinds of surgeons. Family medicine tends to be around $200k. However, this amount ranges vastly by market and top pay often goes to those willing to work in more rural hospitals because no one wants to. For example, pay in NYC for physicians is appalling low compared to the rest of the U.S. market. In addition, certain systems have hard caps. For example, the VA hospitals cap physician pay inclusive of bonus at $400k. This is documented and you can in fact just look up a random doc at the VA with one of the many federal pay search tools.

While some doctors can make more, it typically because they own a practice and that increased pay comes from good old fashioned capitalism. Meaning, they tax the amount their nurses, NPs, medical assistants, etc. make just like all businesses make money per head on their employees. Whether you believe this is right or wrong is up to you. However, this is not any different that someone who runs, for example, a yard care business. More accurate pay can be found by those who work directly for large hospitals.

Next, the cost of medical education in the United States is vastly higher than other countries. Right now, medical school will cost you somewhere from $400-600k. This is in addition to whatever debt accrued during undergraduate. Further, medical school applications are highly competitive, so students often accrue additional debt by completing a masters in something like public health prior to entry to medical school. This means that someone may have upwards of $750k of debt when they finish medical school, but they still have somewhere between 3-10 years of residency and fellowship before they make attending money. During this time, the debt accrues interest and balloons.

Now, once you become an attending, you're still not good and expenses are vast. Shift work can vary from something like 7 12-hour shifts in a row for intensivists to 14 shifts in a row for hospitalists. Note, just because it says its a 12-hour shift doesn't mean you work 12 hours. They still need to chart and bill and if it's busy, that may be another few hours after the shift is over. In some remote clinics, an ER physican may work 7 24-hour shifts in a row. That may sound absurd and unsafe and it likely is, but it's the reality of the work. If someone is working that schedule, they have increased expenses to just, frankly, live. On the low end, it's very difficult to cook in that environment, so you have to buy a lot of premade food. On a more expensive end, having children on this schedule is extremely difficult. You either require a spouse that doesn't work or you need something like a night nanny. If you're working 12 hour shifts, you must sleep at night and you can't be up to take care of a baby otherwise you run the risk of killing someone the next day. Unless you're paying someone under the table, current nanny rates in large markets are about $20-25/hour. Insurance rates are also high. I don't mean malpractice either. Generally speaking, one needs to carry disability insurance because if one gets into a car accident and breaks their magic hands, there's no way to pay back that debt otherwise. These policies are thousands a year. That's just the start. They pay a large amount of money to buy their time back because they don't have it.

Next, there's a myth about limiting residency slots in order to increase pay, at least recently. I will not defend the AMA and some of they took, especially in the 1990s. Here's the 2025 residency match data:

https://www.nrmp.org/match-data/2025/05/results-and-data-202...

The number of offered and filled slots is on page 2 (or 13 depending on how you count). Some specialties filled all of their slots. Where the U.S. vastly lacks is pediatricians, family medicine, internal medicine (who can work like family medicine if need be.) Pediatricians had 147 unfilled slots. Family medicine had 805 unfilled spots. Internal medicine had 357 unfilled spots. These spots can be filled by people who graduated from U.S. medical schools, island medical schools, Mexican medical schools, or a vast array of other foreign medical schools. However, they're not filled because they don't have the applicants. That's not medical school collusion. That's the hard reality that medical school is extremely expensive and the training is extremely long.

Now, how do other countries handle things? One, their medical school is not as crushingly expensive. Two, places like Europe cap the number of hours a physican can work. If you want to pay American physicians less, you'd need to blow out their medical school debt, reduce their hours, and offer better benefits. Until then, no, really, they're not overpaid.

If you want to start pointing fingers, try the vertical integration of insurance companies, pharmacy benefit managers, and hospitals. I don't have the numbers readily available, so I'll stop here. But, really, it's not the docs.

kxyvr commented on Matrices can be your friends (2002) sjbaker.org/steve/omniv/m... · Posted by u/todsacerdoti

Viliam1234 · 5 months ago

> Mathematicians like to see their matrices laid out on paper this way (with the array indices increasing down the columns instead of across the rows as a programmer would usually write them).

Could a mathematician please confirm of disconfirm this?

I think that different branches of mathematics have different rules about this, which is why careful writers make it explicit.

kxyvr · 5 months ago

I'm an applied mathematician and this is the most common layout for dense matrices due to BLAS and LAPACK. Note, many of these routines have a flag to denote when working with a transpose, which can be used to cheat a different memory layout in a pinch. There are also parameters for increments in memory, which can help when computing across a row as opposed to down a column, which can also be co-opted. Unless there's a reason not to, I personally default to column major ordering for all matrices and tensors and use explicit indexing functions, which tends to avoid headaches since my codes are consistent with most others.

Abstractly, there's no such thing as memory layout, so it doesn't matter for things like proofs, normally.

kxyvr commented on Differentiable Programming from Scratch thenumb.at/Autodiff/... · Posted by u/sksxihve

FilosofumRex · a year ago

Historical fact: Differentiable programming was a little known secret back in the 90's, used mainly by engineers simulating numerically stiff systems like nukes and chemicals in FORTRAN 95. It then disappeared for nearly 30 yrs before rediscovery by the ML/AI researchers!

kxyvr · a year ago

Automatic differentiation was actively and continuously used in some communities for the last 40 years. Louis Rall has an entire book about it published in 1981. One of the more popular books on AD written by Griewank was published in 2000. I learned about it in university in the early 2000s. I do agree that the technology was not as well used as it should have been until more recently, but the technology was well known within numerical math world and used continuously over the years.

kxyvr commented on How a Forgotten Battle Created a More Peaceful World worldhistory.substack.com... · Posted by u/crescit_eundo

BurningFrog · a year ago

You're listing pretty much all the wars of that era.

That adds up to about 5 years or less at war for almost all European countries. Probably the most peaceful century in the history of Europe.

During this time, European population also doubled, life expectancy increased by 10-15 years, and GDP/person more than doubled.

kxyvr · a year ago

That's not true. Here's an abbreviated list from:

http://historyguy.com/major_wars_19th_century.htm

I'm sure there are others. It lists:

  Greek War of Independence (1821-1832)
  French invasion of Spain (1823)
  Russo-Persian War (1826-1828)
  Russo-Turkish War (1828-1829)
  Hungarian Revolution and War of Independence (1848-1849)
  First Schleswig War (1848-1851)
  Wars of Italian Independence (1848–1866)
  Crimean War (1854–1856)
  Second Schleswig War (1864)
  Austro-Prussian War (1866)
  Franco-Prussian War (1870-1871)
  Russo–Turkish War (1877–1878)
  Serbo-Bulgarian War (1885)
  Greco–Turkish War (1897)

Together, that adds up to multiple decades of war.

kxyvr commented on A $100 DIY muon tomographer spectrum.ieee.org/diy-muo... · Posted by u/Luc

ajb · a year ago

This is pretty cool.

The title here is incorrect; this is not tomography (and the OP doesn't claim it is). The article mentions tomography but what's happening here is individual measurements.

Tomography is also pretty cool, although the math is pretty painful (Terry Tao has papers on it)

kxyvr · a year ago

True. That said, I'll also mention that tomography is a very rich, interesting field that's still open to new innovations. I work in the area and unfortunately needed to pass on a muon tomography contract some years ago. By the way, you may know this, but the following is for the broader audience.

---

If anyone is interested, the book Parameter Estimation and Inverse Problems by Aster, Borchers, and Thurber give an easy introduction to simple tomography problems in their book. Example 1.12 in their second edition has a very basic setup. More broadly, tomography intersects with an area of study called PDE constrained optimization. Commonly, tomography problems are setup as a large optimization problem where the difference between experimental data and the output of a simulation are minimized. Generally, the simulation is parameterized on the material properties of whatever is under study and are the optimization variables. The idea is that whatever material property that produces a simulation that matches the experimental data is probably what's there. This material property could be something simple like density or something more complicated like a full elasticity tensor.

What makes this difficult, is that most good simulations come from a system of differential equations, which are infinite dimensional and not suitable for running directly in an optimization algorithm. As such, care must be taken into discretizing the system carefully, so that the optimization tool produces something reasonable and physical. Words you'll see are things like discretize-then-optimize or optimize-then-discretize. Generally speaking, the whole system works very, very poorly if one just takes an existing simulator and slaps an optimizer on it. Care must be taken to do it right.

As far as the optimizer, the scale is pretty huge. It's common to see hundreds of millions of variables if not more. In addition, the models normally need to be bounded, so there are inequalities that must be respected. For example, if something like a density isn't bounded to be positive (which is physical), then the simulator itself may diverge (a simulator here may be something like a Runge-Kutta method.)

Anyway, it's a big combination of numerical PDEs, optimization, HPC, and other tools just to get a chance to run something. Something like the detector in the article is very cool because it may be a realistic way to get data to test against for super cheap.

kxyvr commented on Minimum bipartite matching via Riemann optimization (2023) ocramz.github.io/posts/20... · Posted by u/f1shy

Xcelerate · a year ago

Funny how things I never expect to see on here pop up occasionally. I had read some of the early papers by Boumal on optimization over Riemannian manifolds in 2016 for a similar problem and even wrote some Julia code for it (before manifolds.jl existed).

In my case, I was trying to perform synchronization over a set of noisy point clouds to extract the "ground truth" point cloud. I.e., take the set of coordinates corresponding to a point cloud, randomly permute the order of the coordinates, randomly rotate/reflect the point cloud, and then apply a Gaussian perturbation to each coordinate. Repeat this process multiple times. The goal then is to recover the original point cloud from the noisy rotated/reflected/permuted copies of the original.

Boumal and Singer had done some work to solve this problem for just rotations/reflections by essentially "stacking" the unknown orthogonal matrices (i.e., elements of O(3)) into a Stiefel manifold and then performing Riemannian optimization over this manifold. It worked fantastically well and was much faster than prior techniques involving semidefinite programming, so I decided to try the same approach for synchronization over permuted copies of the point cloud, and it also worked quite well. However, one can achieve better convergence properties by performing a discrete Fourier transform over the symmetric group on the sets of point clouds so that instead of optimizing over a Stiefel manifold that is supposed to represent stacked permutation matrices (well, stacked orthogonal matrices with constraints to make them doubly stochastic), you optimize over a manifold of stacked unitary matrices intended to represent irreps of S_n.

Ultimately I didn't know enough group theory at the time to figure out how to generate irreps for the "combined" group of O(3) and S_n, so I couldn't solve the problem simultaneously for both rotations/reflections and permutations, but ultimately Singer and Boumal developed an approach that bypassed the synchronization problem altogether by utilizing invariant polynomials to extract the ground truth signal in a more direct way.

kxyvr · a year ago

I believe Absil, Mahony, and Sepulchre also have a book on optimization over manifolds:

https://press.princeton.edu/absil

I was unaware of the Bournal work, so thanks for that. Do you have any idea how Bournal's approach differs from Absil's?

For others, it looks like Bournal also has a book on the topic from 2023:

https://www.nicolasboumal.net/book/