The GRE is useful; range restriction is a thing

The above figure is from Beyond the Threshold Hypothesis: Even Among the Gifted and Top Math/Science Graduate Students, Cognitive Abilities, Vocational Interests, and Lifestyle Preferences Matter for Career Choice, Performance, and Persistence. It shows that even at very high levels of attainment on standardized tests there are differences in life outcome based on variation. The old joke is that results on intelligence tests don’t matter beyond a certain point…that point being whatever your own position is! But these results show that mathematics SAT outcomes at age 13 can still predict a lot of things across a wide range.

From personal experience people outside of psychology are pretty unaware of the power of cognitive aptitude testing. This includes many biologists. I was reminded of the above figure as I read portions of Richard Haier’s . If you are a biologist curious about the topic, this is a highly recommended book.

The main reason I am posting this is that this it was asked of me by a friend in academia. There has recently been a backlash against the GRE exam, with support from the highest echelons of the science media. Additionally, many researchers in public forums are voicing objections to the GRE very vocally. Naturally this has resulted in counterarguments…but respondents have to be very careful how the couch their disagreement, because they fear being accused of being racist, sex, or classist. Such accusations might trigger social media mobs, which no one wants to be the target of (and if past experience is any guide, friends and colleagues will stand aside while the witch is virtually burned, hoping to avoid notice).

Because of the request above I finally decided to look at the two papers which are eliciting the current wave of GRE-skepticism, The Limitations of the GRE in Predicting Success in Biomedical Graduate School and Predictors of Student Productivity in Biomedical Graduate School Applications. To my eye they suffer from the same problem as all earlier criticisms: range restriction.

The issue is that if a university is using the GRE and other metrics well as filters for those admitted then there shouldn’t be that much variation in outcome left (the outcome being publications or some other important metric which actually leads to the production of science, as opposed to test scores and grades). The two papers above look at those admitted to biomedical programs at UNC and Vanderbilt, while another study looked at UCSF. These are all universities with standards high enough that there are either explicit or implicit cut-off scores so that many students are removed from the applicant pool immediately (the mean scores are well above the 50th percentile, you can see them in the paper yourself).

When I was in graduate school I was on a fellowship committee for several years, and I had access to GRE scores and grades. But I didn’t really pay much attention to them because there wasn’t that much range. And to be honest if the student was beyond their first year I didn’t look at all as time went on. In contrast, I did look really closely at the recommendations from their advisors. From talking to others on the committee this seemed typical. Once students were admitted they were judged based on how they were doing in graduate school. And how they were doing in graduate school had to do with research, not their graduate school GPA or what they scored on the GRE to get in.

As an empirical matter I do think that it is likely many universities will follow the University of Michigan in dropping the GRE as a requirement. There will be some resistance within academia, but there is a lot of reluctance to vocally defend the GRE in public, especially from younger faculty who fear the social and professional repercussions (every time a discussion pops up about the GRE I get a lot of Twitter DMs). My prediction is that after the GRE is gone people will simply rely on other proxies.

If the GRE is not required, but can be taken, then students who do well on the GRE will put that on their application. Sometimes strong students encounter tragedies in their undergraduate years which strongly impact their grade point averages, and very strong GREs can help show admissions committees that they can do the coursework despite their undergraduate record (I’m not positing a hypothetical, but recounting real individuals I’ve known of and seen). It seems cruel to deny these students the chance to submit their test scores. This means that those professors who believe the GRE is valid will show preference to students who take the test and have strong scores (and to be sure, many more care about the GRE when it means someone concretely joining their lab, as opposed to the abstraction of who gets admitted to the department).

More broadly, professors who are taking students will look more at proxies for GRE score, such as undergraduate institution, or the prestige of the recommendation letters. In some places, such as Britain, standardized testing emerged in part as a way to identify strong students from underprivileged backgrounds. These are not the type of students who would ever be able to present a prestigious letter of recommendation. This is a sort of student which still exists (often they are from non-academic backgrounds, being the first to graduate from college in their family; what they lack in polish they compensate for in aptitude, but that take the right environment to express).

The recourse to other variables besides the GRE score will likely have mixed results at best. Consider the successful campaign to ban asking for job applicants’ criminal records. It turns out that just increased discrimination against all young black men, because employers could not longer differentiate. In general I think removing the GRE would probably hurt graduates of less prestigious state universities the most if I had to guess (and of course students from East Asia, who tend to have a comparative advantage on standardized tests). I’m pretty sure we’ll see.

The issue is with the model, not precision!

The Wirecutter has a thorough review of direct-to-consumer ancestry testing services. Since I now work at a human personal genomics company I’m not going to comment on the merits of any given service. But, I do want to clarify something in regards to the precision of these tests. Before the author quotes Jonathan Marks, he says:

For Jonathan Marks, anthropology professor at University of North Carolina at Charlotte, the big unknown for users is the margin for error with these estimates….

The issue I have with this quote is that the margin of error on these tests is really not that high. Margin of error itself is a precise concept. If you sample 1,000 individuals you’ll have a lower margin of error than if you sample 100 individuals. That’s common sense.

But for direction-to-consumer genomic tests you are sampling 100,000 to 1 million markers on SNP arrays (the exact number used for ancestry inference is often lower than the total number on the array). For ancestry testing you are really interested in the 10 million or so (order of magnitude) markers which vary between population, and a random sampling of 100,000 to 1 million is going to be pretty representative (consider that election year polling usually surveys a few thousand people to represent an electorate of tens of millions).

If you run a package like Admixture you can repeat the calculation for a given individual multiple times. In most cases there is very little variation between replicates in relation to the percentage breakdowns, even though you do a random seed to initialize the process as it begins to stochastically explore the parameter space (the variance is going to be higher if you try to resolve clusters which are extremely phylogenetically close of course).

As I have stated before, the reason these different companies offer varied results is that they start out with different models. When I learned the basic theory around phylogenetics in graduate school the philosophy was definitely Bayesian; vary the model parameters and the model and see what happens. But you can’t really vary the model all the time between customers, can you? It starts to become a nightmare in relation to customer service.

There are certain population clusters that customers are interested in. To provide a service to the public a company has to develop a model that answers those questions which are in demand. If you are designing a model for purely scientific purposes then you’d want to highlight the maximal amount of phylogenetic history. That isn’t always the same though as the history that customers want to know about it. This means that direct-to-consumer ethnicity tests in terms of the specification of their models deviate from pure scientific questions, and result in a log of judgment calls based on company evaluations of their client base.

Addendum: There is a lot of talk about the reference population sets. The main issue is representativeness, not sample size. You don’t really need more than 10-100 individuals from a given population in most cases. But you want to sample the real population diversity that is out there.

Open Thread, 9/3/2017

I found the above video through Rod Dreher. It touched me on a visceral level because the baby in the first portion looks strikingly like my youngest. He’s sitting and smiling so much now. Really appreciating his infant-hood, as this is the third time we’re going through this.

All I can say in relation to having children is that now I know what matters, all that matters, and that none of the rest matters.

The penultimate season of has come and gone. They’re really compressing a lot of material into only a few episodes. I didn’t watch the earlier seasons before the show got ahead of the books, but I have to think they were more leisurely. I’ll watch the final season to get a sense of the ending in the books in case George R. R. Martin doesn’t finish them, but I think the sprint to the finish line means that if he does write the remaining books he’ll have a lot of free territory to himself.

Now on Stage: The Countdown to a New Taylor Swift Album. Streaming has gone from 23 to 63 percent of the market in three years.

Neanderthals and Denisovans as biological invaders.

Evolutionary biology today and the call for an extended synthesis.

The second sage. The fact that Westerners don’t know who Mencius is (a premise of the piece) is ridiculous. But probably true. I would still recommend for another early Confucian viewpoint.

I added a disclosures page. Mostly all that matters right now is that I work at Insitome, trying to do interesting things in the personal genomics space (and now that the Helix store is open you can purchase our first offering).

If you haven’t, please sign-up for my newsletter. I’m seeing more and more despondency on the nature of Twitter from the people who use it the most and produce the vast majority of the content. I suspect it will collapse sooner than later….

The Looming Decline of the Public Research University. As someone with intellectual aspirations but a conservative political viewpoint I’m conflicted. On the one hand the academy produces great work. On the other hand a lot of academics don’t see a difference between someone like me and Nazis (judging by “likes” of things I’ve retweeted to test the waters in relation to those promoting the proposition). Like it or not many conservatives perceive that a subset of the academy is dangerous to us on existential grounds. Why should we pay for our own destruction? If we could surgically remove these departments then the university could maintain itself, but that seems impossible. So you see where the future leads.

This is probably the worst US flood storm ever, and I’ll never be the same. “…Houston may not be a nice place to visit, but you would want to live there. I do.”

The Best DNA Ancestry Testing Kit. There is some good and some bad in this review. But it’s thorough.

Fun fact, 44% of this site’s traffic is now mobile.

Rohingya unmasking complexity in a world we want simple

There is currently a major humanitarian crisis in Burma as Rohingya Muslims flee conflict between the military and separatist militants. Obviously this is a developing story. Unfortunately, very few in the West and the media have a well developed understanding of the history of Burma. Therefore the easiest framework is something worthy of a DC superhero film: there is the good, and there is the bad.

Just because such black and white dichotomies tend to collapse complexity doesn’t mean they are wrong. In World War II the Nazis were the bad. But details are often illuminating and informative. The Soviet Union was on the side against the Nazis, but it wasn’t exactly a “good” actor. Similarly, Finland at points made common cause with Nazi Germany, but that was less about its affinity with Hitler’s regime and more about surviving a Soviet invasion. There are people who are good and bad. But there are also people in situations, which dictate actions which are bad, or enable actions which seem good. (and a mix)

If you want a broader view of mainland Southeast Asian history, which Burma plays a large part in, I’d recommend . Unlike Africa (with the exception of Ethiopia and Egypt), Indonesia, and much of the Middle East (Iran and Turkey excepted), mainland Southeast Asia developed nation-states organically. Vietnam, Cambodia, Thailand and Burma, were not dreamed up by European colonialists, but evolved through their own historical logic (in this case, the migration out of southern China of Tai peoples and the response of the older Southeast Asian polities, being the central narrative thread).

The only book about Burma’s history I’ve read is . It has a lot of personal detail, as the author is himself a member of the Burmese Diaspora, and seems to come from an elite family with many connections the people who have run the country since independence.

In  the author alludes to the fact that Burma in the early modern period was on the edge of Islamicate civilization. At its peak the Mughal Empire had within its penumbra the Burmese polity, and it was impossible for the latter not to be influenced by the former (the influence actually pre-dates the Mughals, though intensified with them). The Buddhist kings of Arakan styled themselves sultans, and employed Muslims of Indian (or West and Central Asian) origin in their armies.

The descendants of these soldiers are part of the story of Islam in Burma. Too often the media representations of Islam in Burma reduce them to the Rohingya. The reality is that there are several Muslim communities within Burma, with different relationships to the majority Theravada Buddhist ethnicities.  claims that Aung San Suu Kyi herself (or more precisely her father) is in part from a family whose ancestry includes some of these Muslim soldiers.

Aung San Suu Kyi of course is at the heart of current events right now. Many are confused as to why this person, who has put her life on the line to defend the rights of self-determination of the Burmese people in the past, will not speak up for the Rohingya now. To a great extent this reminds me of the Lewis’ trilemma in relation to Jesus, that he was either a liar, lord, or lunatic. For many of us the answer may not be any of the above. Aung San Suu Kyi is a complex person at the heart of complex events. It was easy to portray her as a selfless saint, who was always on the side of the good as we understand it, but current events show that she was never immune to the exigencies of reality and practicality. Just as she was not saint in the past, I doubt she is a monster in the present, even if she has become caught up in events of monstrosity. Remember, if Gandhi was alive today he would surely be excoriated for his lack of solidarity with other people of color at least, and his racism at most.

Stepping aside from Aung San Suu Kyi, I think it is no surprise that democratization of Burmese society and culture has been occurring while there has been a rise in aggressive Buddhist chauvinism. Americans often do not want to admit that democratization and liberal tolerance do not go hand and hand. In places like China, and yes, Burma, authoritarian governments likely keep a lid on ethnic tensions because they are destabilizing for the public order. It was with universal white male suffrage in the United States that the racialized character of the American republic became much more explicit. Similarly, popular nationalism in Europe was associated with drives toward homogeneity and assimilation of subordinate groups.

Why are the Rohingya so hated in Burma? There are several possible reasons:

– They are racially distinct (all the photographs make it clear that they are not physically different from Bengali peasants) from most of the other ethnicities in Burma (including some groups of Muslims who descend from intermarriages with the Bamar majority).

– Their Muslim religion is very distinct from that of the dominant culture in Burma, Theravada Buddhism. Unlike China, where Buddhism is a strand within the national culture (and not a dominant one), in Burma Buddhism occupies the role that Christianity does in Northern Europe: the religion’s arrival was associated with the rise of complex societies, and political self-awareness. Though the Theravada Buddhism of Burma has local flavors (nat worship), it unites many of the disparate ethno-linguistic groups together, from the majority Bamar, to the Tai Shan, to the Austro-Asiatic Mon.

The Muslim religion of the Rohingya also enforces a stronger divergence from the majority religion than the Hindu background of other South Asians in Burma. Though most Indians left Burma in the years after independence, a substantial number have remained. The ethnographic literature I’ve seen indicates that many have re-identified as Theravada Buddhist, though no doubt maintaining many Hindu customs and practices within the community. This is not that difficult when you consider that Burmese Buddhism has many indigenous and Hindu influences already. Additionally, Hinduism and Buddhism are connected traditions, and arguably exhibit a level of commensurability that makes identity switching less stressful for both individuals and communities.

– They are perceived to relatively recent migrants to the Arakan coast from Bengal, and so not an indigenous ethnic community within Burma. Note that there are Muslim communities, even within Arakan, which are not Rohingya, which are recognized as indigenous. Not only are they perceived to be migrants, but their numbers threaten the dominance of the Rakhine people of the region.

In highlighting these elements I’ve suggesting that the Rohingya are arguably the most marginalized group in Burma. There are other Muslims ethnicities in Burma, but most are not demographic threats, derive from attested older migration events, and have intermarried with local populations so that the physical differences are not quite as salient. There are Christian minorities, such as the Chin, which have been targeted for persecution based on the religious differences, but the Chin are not perceived to be alien to Burma, simply unassimilated to dominant Theravada cultural complex. Additionally, there is no large racial difference between the Chin and the Theravada groups.

Much of the public debate revolves around the issue of Rohingya indigeneity or lack thereof. Though I have only modest confidence in my position, I believe that most of the Rohingya presence in Arakan dates to the period of British rule. Though the Rohingya language is not intelligible with standard Bengali, it is rather close to the dialect of southeast Bangladesh, Chittagong. My family is from Comilla, which borders the Indian state of Tripura. When I listen to Rohingya speak it’s only slightly less intelligible to me than the dialect of West Bengal (which is the basis for standard Bengali). In fact, the accent of Rohingya men is uncannily similar to what I remember from peasants in rural southeast Bangladesh when I visited in 1990!

If the Rohingya are not Bengali, they are something very close.

But the Rohingya will tell you something different. They do not self-identify as Bengalis, but as Burmese. Additionally, like some South Asian Muslims they deemphasize their South Asian origins, and create fictive extra-South Asian genealogies. It is important to note that the Rohingya do not write their language in the Bengali script. This means that their intelligentsia has no strong consciousness of being Bengali, because they are not part of the world of Bengali letters.

Earlier on I noted that mainland Southeast Asian had polities which easily transitioned to nation-states, because of the organic development of their identities. This is not true in South Asia. There is a bit of artificiality in the construction of South Asian polities (perhaps with the exceptions of Bhutan and Sri Lanka). Though South Asians no matter their identity are clearly defined and demarcated from other peoples, among themselves religion and community, rather than nationality scale ethnic identity, have been paramount.

In  the author points out that a Bengali cultural identity evolved relatively slowly over the past 1,000 years. He makes the case that the Islamic character of eastern Bengal had to do with its underdeveloped state, and that land reclamation projects under the aegis of Islamic polities stamped the local peasantry who were settling the territory with the religion of the regnant order. And yet until recently the Muslim elite of Bengal was not culturally Bengali; they were Urdu speaking. The Bengali dialects of the peasantry were not prestigious, while the Bengali Renaissance was predominantly driven by upper case Hindus who helped shaped what standard Bengali became.

I will elide over the details of the emergence of a self-consciously Bengali and Muslim intelligentsia. It is something which I am only aware of vaguely, though I have seen fragments of it in my own extended family and lineage, as people from Urdu-speaking backgrounds have allowed their children to grow up speaking only Bengali, and fully assimilated to a Bengali identity without any qualification.

But the development of a Bengali and Muslim self-identity was occurring at the same time the ancestors of the Rohingya were pushing beyond the borders of traditional Bengal, into Arakan. Their lack of Bengali identity comes honestly because peasant identity has always been more localized and inchoate, and the Rohingya intelligentsia crystallized around other identifiers which could distance themselves from their relationship to Bengalis. In particular, the Rohingya seem more uniformly Islamic in their orientation. The female anchor for Rohingya news updates always seems to wear a headscarf, as opposed to those for Dhaka news reports.

In the short-term the killing of infants and raping of women has to stop. But these simple answers have behind them lurking deeper complexities. While agreeing upon the urgency of action now, we need to be very careful to not turn complex human beings into angels and demons. We have enough history in the recent past that that sort of model only leads to tragedy down the line, as those who we put utmost faith in fail us due to their ultimate humanity.

Two thousand years of philosophy on the margin

A little less than two years ago I began to read Anthony Kenny’s . It’s a big book, on the order of ~1000 pages. But that’s not the reason I’m just now finishing it. The book is divided by chronologically and thematically. I read about the ancients in about a week, but struggled to get past the medieval section. I’ve mentioned this before.

And yet in my self-pity I did wonder: is this partly just a function of the fact that ancient philosophy provided most of the answers (or non-answers) in what we think of as philosophy over a few centuries? As they say, perhaps the rest is simply commentary and extension.

If society collapsed and we reverted to barbarism it seems it would be a loss if we didn’t have the . But if we had philosophy up to Seneca, would we miss what came after?

People believe in evolution, just not for humans

The term “liberal Creationism” refers to the fact that on the cultural Left there is a strong belief in the concept of evolution on the whole, but in the case of human beings biological evolutionary processes are seen as marginal in comparison to culture. In other words, natural selection and adaptation explain the diversity around us in the animal and plant world, but can tell us little about human beings.

This viewpoint exhibits various degrees of sophistication, but I think it gets at a real deeply held perspective (though not universal one, in it is recounted that Noam Chomsky held his fire during the sociobiology controversy in part because he was quite open to the idea that behavior could have some biological basis).

Looking at the General Social Survey though, I believe now that the liberal Creationist viewpoint is actually just a spin on the normal American position. That is, Americans as a whole are quite open to the idea of descent with modification and common ancestry in the context of animals, but much more squeamish when it comes to humans. Some conservative religious Creationists admit this rather frankly. Their objection to evolution is not about science, but about human dignity. In fact I believe William Jennings Bryan’s Creationism mostly just involved special creationism for human beings. The rest was not important to him.

A new GSS variable, EVOLVED2, which complements an older variable, EVOLVED, allows us to explore this question directly.

Here is what they ask:

EVOLVED: Human beings, as we know them today, developed from earlier species of animals. (Is that true or false?)

EVOLVED2: Elephants evolved from earlier species. (Is that true or false?)

53 precent of respondents answered yes to true in the first case, but 86 percent in the second case. In other words, presenting evolution in a non-human context reduces resistance.

You can check the responses against attitudes toward the literality of the Bible:

I think this suggests to us that on a broader social scale resistance to evolution is culturally conditioned, and derives from deep intuitions about human dignity. The specific details of where that dignity comes from, whether it be Protestant Fundamentalist or Social Justice is incidental.

Heraclius was a great man, but a dirty old man

The Emperor Heraclius is someone who more people should know. He saved the Byzantine Empire before it truly became the Byzantine Empire in a mature form. When he took power the Persians were on the march, and ruled vast swaths of the Asian and African possessions of the East Roman Empire. Theodore of Tarsus, one of the early Archbishops of Canterbury, grew up under Persian rule. Like Hannibal’s early victories Heraclius’ defeat of the Persians is a tour de force of strategic brilliance. I’ll leave it to the reader to find out why themselves (I recommend to any reader).

But this post is inspired by pop-culture. People are talking about nephew-aunt relations right now. As it happens Heraclius’ second wife was his niece, Martina. Here is something I found on Wikipedia: “He had two children with Fabia and at least nine with Martina, most of whom were sickly children…Fabius (Flavius) had a paralyzed neck and Theodosios, who was a deaf-mute….” The history of this period can be patchy and unreliable. So I’m not sure there were nine children and most were sickly…but probably inbreeding was causing some serious issues.

Genetics books for the masses!

Since I’ve become professionally immersed in genetics I haven’t read many books on the topics. I read papers. And I do genetics. But back in the day I did enjoy a good book. The standard recommendation would be to read Matt Ridley’s . It’s a bit dated now (it was published around when the Human Genome Project being completed), but I’d still recommend it.

But when in the mid-2000s I dabbled a little bit in the world of worm (C. elegans) genetics I read Andrew Brown’s . It’s pretty far from my current concerns and fixations, with more of a focus on developmental processes, but it is pretty cool to read about the race to “map” every cell in C. elegans.

The second book I’d recommend readers of this blog is the late Will Provine’s . Modern population genomics is a massive edifice built atop the foundations of the early 20th century fusion of Mendelism and the biometrical heirs of Darwin. Provine outlines how primitive genetics eventually seeded the birth of the Neo-Darwinian Synthesis.

Why do percentage estimates of “ancestry” vary so much?

When looking at the results in , , and my “East Asian” percentage is:

– 19%
– 13%
– 6%

What’s going on here? In science we often make a distinction between precision and accuracy. Precision is how much your results vary when you re-run an experiment or measurement. Basically, can you reproduce your result? Accuracy refers to how close your measurement is to the true value. A measurement can be quite precise, but consistently off. Similarly, a measurement may be imprecise, but it bounces around the true value…so it is reasonably accurate if you get enough measurements just cancel out the errors (which are random).

The values above are precise. That is, if you got re-tested on a different chip, the results aren’t going to be much different. The tests are using as input variation on 100,000 to 1 million markers, so a small proportion will give different calls than in the earlier test. But that’s not going to change the end result in most instances, even though these methods often have a stochastic element.

But what about accuracy? I am not sure that old chestnuts about accuracy apply in this case, because the percentages that these services provide are summaries and distillations of the underlying variation. The model of precision and accuracy that I learned would be more applicable to the DNA SNP array which returns calls on the variants; that is, how close are the calls of the variant to the true value (last I checked these are arrays are around 99.5% accurate in terms of matching the true state).

What you see when these services pop out a percentage for a given ancestry is the outcome of a series of conscious choices that designers of these tests made keeping in mind what they wanted to get out of these tests. At a high level here’s what’s going on:

  1. You have a model of human population history and dynamics with various parameters
  2. You have data that that varies that you put into that model
  3. You have results which come back with values which are the best fit of that data to the model you specificed

Basically you are asking the computational framework a question, and it is returning its best answer to the question posed. To ask whether the answer is accurate or not is almost not even wrong. The frameworks vary because they are constructed by humans with difference preferences and goals.

Almost, but not totally wrong. You can for example simulate populations whose histories you know, and then test the models on the data you generated. Since you already know the “truth” about the simulated data’s population structure and history, you can see how well your framework can infer what you already know from the patterns of variation in the generated data.

Going back to my results, why do my East Asian percentages vary so much? The short answer is that one of the major variables in the model alluded to above is the nature of the reference population set and the labels you give them.

Looking at Bengalis, the ethnic group I’m from, it is clear that in comparison to other South Asian populations they are East Asian shifted. That is, it seems clear I do have some East Asian ancestry. But how much?

The “simple” answer is to model my ancestry is a mix of two populations, an Indian one and an East Asian one, and then see what the values are for my ancestry across the two components. But here is where semantics becomes important: what is Indian and East Asian? Remember, these are just labels we give to groups of people who share genetic affinities. The labels aren’t “real”, the reality is in the raw read of the sequence. But humans are not capable of really getting anything from millions of raw SNPs assigned to individuals. We have to summarize and re-digest the data.

The simplest explanation for what’s going on here is that the different companies have different populations put into the boxes which are “Indian/South Asian” and “East Asian.” If you are using fundamentally different measuring sticks, then there are going to be problems with doing apples to apples comparisons.

My personal experience is that 23andMe tends to give very high percentages of South Asian ancestry for all South Asians. Because “South Asian” is a very diverse category when tests come back that someone is 95-99% South Asian…it’s not really telling you much. In contrast, some of the other services may be using a small subset of South Asians, who they define as “more typical”, and so giving lower percentages to people from Pakistan and Bengal, who have admixture from neighboring regions to the west and east respectively.*

Something similar can occur with East Asian ancestry. If the “donor” ancestral groups are South Asian and East Asian for me, then the proportions of each is going to vary by how close the donor groups selected by the company is to the true ancestral group. If, for example,  chose a more Northeastern Asian population than , then my East Asian population would vary between the two services because I know my East Asian ancestry is more Southeast Asian.

The moral of the story is that the values you obtain are conditional on the choices you make, and those choices emerge from the process of reducing and distilling the raw genetic variation into a manner which is human interpretable. If the companies decided to use the same model, the would come out with the same results.

* I helped develop an earlier version of MyOrigins, and so can attest to this firsthand.