You know the story about the male Victorian physicians who unwittingly produced orgasms in their female clients by treating them for “hysteria” with newly-invented, labor-saving, mechanical vibrators? It’s little more than an urban legend albeit one transmitted through academic books and articles. Hallie Lieberman and Eric Schatzberg, the authors of a shocking new paper, A Failure of Academic Quality Control: The Technology of Orgasm, don’t quite use the word fraud but they come close.
Since its publication in 1999, The Technology of Orgasm by Rachel Maines has become one of the most widely cited works on the history of sex and technology (Maines, 1999). This slim book covers a lot of ground, but Maines’ core argument is quite simple. She argues that Victorian physicians routinely treated female hysteria patients by stimulating them to orgasm using electromechanical vibrators. The vibrator was, according to Maines, a labor-saving technology that replaced the well-established medical practice of clitoral massage for hysteria. She states that physicians did not perceive either the vibrator or manual massage as sexual, because neither method involved vaginal penetration.
This argument has been repeated in dozens of scholarly works and cited with approval in many more. A few scholars have challenged various parts of the book. Yet no scholars have contested her central argument, at least not in the peer-reviewed literature. Her argument even spread to popular culture, appearing in a Broadway play, a feature-length film, several documentaries, and many mainstream books and articles. This once controversial idea has now become an accepted fact.
But there’s only one problem with Maines’ argument: we could find no evidence that physicians ever used electromechanical vibrators to induce orgasms in female patients as a medical treatment. We examined every source that Maines cites in support of her core claim. None of these sources actually do so. We also discuss other evidence from this era that contradicts key aspects of Maines’ argument. This evidence shows that vibrators were indeed used penetratively, and that manual massage of female genitals was never a routine medical treatment for hysteria.
… the 19-year success of Technology of Orgasm points to a fundamental failure of academic quality control. This failure occurred at every stage, starting with the assessment of the work at the Johns Hopkins University Press. But most glaring is the fact that not a single scholarly publication has pointed out the empirical flaws in the book’s core claims in the 19 years since its release.
Wow. Read the whole thing.
Hat tip: Chris Martin on twitter.
It is commonly believed that medical research spending is biased against women. Here are some representative headlines: Why Medical Research Often Ignores Women (Boston University Today), Gender Equality in Medical Research Long Overdue, Study Finds (Fortune), A Male Bias Reigns in Medical Research (IFL Science). Largely on the basis of claims like this the NIH set up a committee to collect data on medical research funding and gender and they discovered there was a disparity. Government funded medical research favors women.
The Report on the Advisory Committee on Research on Women’s Health used the following criteria to allocate funding by gender:
All funding for projects that focus primarily on women, such as the Nurses’ Health Study, the Mammography Quality Standards Act, and the Women’s Health Initiative, should be attributed to women. For research, studies, services, or projects that include both men and women, recommended methods to calculate the proportion of funds spent on women’s health are as follow:
a. If target or accrual enrollment data are available, multiply the expenditure by the proportion of female subjects included in the program. For example, if 50 percent of the subjects enrolled in a trial, study, service, or treatment program are women, then 50 percent of the funds spent for that program should be counted as for women’s health. On the other hand, for diseases, disorders, or conditions without enrollment data, expenditures can be calculated based on the relative prevalence of that condition in women.
b. Where both males and females are included, as may be the case for many basic science research projects, multiply the expenditure by 50 percent.
On the basis of these criteria the report finds that in almost every category there is more female-focused NIH funding than male-focused NIH spending with the totals more than two to one in favor of females ($4.5 billion to $1.5 billion). Now personally I don’t regard this as a terrible “bias” as most spending ($25.7 billion) is for human beings and I don’t see any special reason why spending on women and men should be equal. It does show, however, that the common wisdom is incorrect. The Boston University Today piece I linked to earlier, for example, motivated its claim of bias in funding with the story of a female doctor who died of lung cancer. The NIH data, however, show a large difference in favor of women–$180 million of NIH lung cancer funding was focused on women while just $318 thousand was focused on men ($135 million wasn’t gender focused).
What about clinical trials? Well for NIH-funded clinical trials the results favor women:
Enrollment of women in all NIH-funded clinical research in FY 15 and FY 16 was 50 percent or greater. Enrollment of women in clinical research was highest in the intramural research program at 68 percent for both FY 15 and FY 16.
In the most clinically-relevant phase III trials:
NIH-defined Phase III Clinical Trials are a subset of NIH Clinical Research studies. The proportion of female participants enrolled in NIH-defined Phase III Clinical Trial was 67 percent in in FY 15 and 66 percent in FY 2016.
Historically, one of the reasons that men have often been more prevalent in early stage clinical trials (trials which are not always meant to treat a disease) is that after the thalidomide disaster the FDA issued a guidance document which stated that women of child-bearing age should be excluded from Phase 1 and early Phase 2 research, unless the studies were testing a drug for a life-threatening illness. That guidance is no longer in effect but the point is that interpreting these results requires some subtlety.
The NIH funds more clinical trials than any other entity but overall more clinical trials are conducted by industry. FDA data indicate that in the United States overall (the country where by far the most people are enrolled in clinical trials) the ratios are close to equal, 49% female to 51% male, although across the world there are fewer women than men in clinical trials, 43% women to 57% men for the world as whole with bigger biases outside the United States.
It would be surprising if industry research was biased against women because women are bigger consumers of health care than men. The Centers for Medicare and Medicaid Services, find, for example, that:
Per capita health spending for females was $8,315 in 2012, approximately 23 percent more than for males, $6,788
Research indicates that women visit the doctor more frequently, especially as they have children, and tend to seek out more preventive care. The National Center for Health Statistics found that women made 30% more visits to physicians’ offices than men between 1995 and 2011.
Nor is it the case that physicians ignore women. In one study of time use of family physicians and thousands of patients:
After controlling for visit and patients characteristics, visits by women had a higher percent of time spent on physical examination, structuring the intervention, patient questions, screening, and emotional counseling.
Of course, you can always find some differences by gender. The study I just cited, for example, found that “More eligible men than women received exercise, diet, and substance abuse counseling.” One often quoted 2008 study found that women in an ER waited 65 minutes to men’s average of 49 minutes to receive a pain killer. Citing that study in 2013 the New York Times decried that:
women were still 13 to 25 percent less likely than men to receive high-strength “opioid” pain medication.
Today, of course, that same study might be cited as a bias against men as twice as many men as women are dying of opioid abuse. I don’t know what the “correct” numbers are which is why I am reluctant to describe differences in the treatment of something as complex as pain to bias.
Overall, spending on medical research and medical care looks to be favorable to women especially so given that men die younger than women.
Hat tip: Discussants on twitter.
Addendum: I expect lots of pushback and motte and baileying on this post. Andrew Kadar wrote an excellent piece on The Sex-Bias Myth in Medicine in The Atlantic in 1994 but great memes resist data. Also, school summer vacation is not a remnant from when America was rural and children were needed on the farm.
Perhaps it is better to win the silver, to which other life outcomes might this apply?:
This paper compares mortality between Gold and Silver medalists in Olympic Track and Field to study how achievement influences health. Contrary to conventional wisdom, winners die over one year earlier than losers. I find strong evidence of differences in earnings and occupational choices as a mechanism. Losers pursued higher-paying occupations than winners according to individual Census records. I find no evidence consistent with selection or risk-taking. How people respond to success or failure in pivotal life events may produce long-lasting consequences for health.
I was very happy with how this turned out, here is the audio and transcript. Here is how the CWTeam summarized it:
Michael Pollan has long been fascinated by nature and the ways we connect and clash with it, with decades of writing covering food, farming, cooking, and architecture. Pollan’s latest fascination? Our widespread and ancient desire to use nature to change our consciousness.
He joins Tyler to discuss his research and experience with psychedelics, including what kinds of people most benefit from them, what it can teach us about profundity, how it can change your personality and political views, the importance of culture in shaping the experience, the proper way to integrate it into mainstream practice, and — most importantly of all — whether it’s any fun.
He argues that LSD is underrated, I think it may be good for depression but for casual use it is rapidly becoming overrated. Here is one exchange of relevance:
COWEN: Let me try a very philosophical question. Let’s say I could take a pill or a substance, and it would make everything seem profound. My receptivity to finding things profound would go up greatly. I could do very small events, and it would seem profound to me.
Is that, in fact, real profundity that I’m experiencing? Doesn’t real profundity somehow require excavating or experiencing things from actual society? Are psychedelics like taking this pill? They don’t give you real profundity. You just feel that many things are profound, but at the end of the experience, you don’t really have . . .
POLLAN: It depends. If you define profundity or the profound as exceptional, you have a point.
One of the things that’s very interesting about psychedelics is that our brains are tuned for novelty, and for good reason. It’s very adaptive to respond to new things in the environment, changes in your environment, threats in your environment. We’re tuned to disregard the familiar or take it for granted, which is indeed what most of us do.
One of the things that happens on psychedelics, and on cannabis interestingly enough — and there’s some science on it in the case of cannabis; I don’t think we’ve done the science yet with psychedelics — is that the familiar suddenly takes on greater weight, and there’s an appreciation of the familiar. I think a lot of familiar things are profound if looked at in the proper way.
The feelings of love I have for people in my family are profound, but I don’t always feel that profundity. Psychedelics change that balance. I talk in the book about having emotions that could be on Hallmark cards. We don’t think of Hallmark cards as being profound, but in fact, a lot of those sentiments are, properly regarded.
Yes, there are those moments you’ve smoked cannabis, and you’re looking at your hand, and you go, “Man, hands, they’re f — ing incredible.” You’re just taken with this. Is that profound or not? It sounds really goofy, but I think the line between profundity and banality is a lot finer than we think.
COWEN: I’ve never myself tried psychedelics. But I’ve asked the question, if I were to try, how would I think about what is the stopping point?
For my own life, I like, actually, to do the same things over and over again. Read books. Eat food. Spend time with friends. You can just keep on doing them, basically, till you die. I feel I’m in a very good groove on all of those.
If you take it once, and say you find it entrancing or interesting or attractive, what’s the thought process? How do you model what happens next?
POLLAN: That’s one of the really interesting things about them. You have this big experience, often positive, not always though. I had, on balance . . . all the experiences I described in the book, with one notable exception, were very positive experiences.
But I did not have a powerful desire to do it again. It doesn’t have that self-reinforcing quality, the dopamine release, I don’t know what it is, that comes with things that we like doing: eating and sex and sleep, all this kind of stuff. Your first thought after a big psychedelic experience is not “When can I do it again?” It’s like, “Do I ever have to do it again?”
COWEN: It doesn’t sound fun, though. What am I missing?
POLLAN: It’s not fun. For me, it’s not fun. I think there are doses where that might apply — low dose, so-called recreational dose, when people take some mushrooms and go to a concert, and they’re high essentially.
But the kind of experience I’m describing is a lot more — I won’t use the word profound because we’ve charged that one — that is a very internal and difficult journey that has moments of incredible beauty and lucidity, but also has dark moments, moments of contemplating death. Nothing you would describe as recreational except in the actual meaning of the word, which is never used. It’s not addictive, and I think that’s one of the reasons.
I did just talk to someone, though, who came up to me at a book signing, a guy probably in his 70s. He said, “I’ve got to tell you about the time I took LSD 16 days in a row.” That was striking. You can meet plenty of people who have marijuana or a drink 16 days in a row. But that was extraordinary. I don’t know why he did it. I’m curious to find out exactly what he got out of it.
In general, there’s a lot of space that passes. For the Grateful Dead, I don’t know. Maybe it was a nightly thing for them. But for most people, it doesn’t seem to be.
COWEN: Say I tried it, and I found it fascinating but not fun. Shouldn’t I then think there’s something wrong with me that the fascinating is not fun? Shouldn’t I downgrade my curiosity?
POLLAN: [laughs] Aren’t there many fascinating things that aren’t fun?
COWEN: All the ones I know, I find fun. This is what’s striking to me about your answer. It’s very surprising.
W even talk about LSD and sex, and why a writer’s second book is the key book for understanding that writer. Toward the end we cover the economics of food, and, of course, the Michael Pollan production function:
COWEN: What skill do you tell them to invest in?
POLLAN: I tell them to read a lot. I’m amazed how many writing students don’t read. It’s criminal. Also, read better writers than you are. In other words, read great fiction. Cultivate your ear. Writing is a form of music, and we don’t pay enough attention to that.
When I’m drafting, there’s a period where I’m reading lots of research, and scientific articles, and history, and undistinguished prose, but as soon as I’m done with that and I’ve started drafting a chapter or an article, I stop reading that kind of stuff.
Before I go to bed, I read a novel every night. I read several pages of really good fiction. That’s because you do a lot of work in your sleep, and I want my brain to be in a rhythm of good prose.
Defininitely recommended, as is Michael’s latest book How to Change Your Mind: What the New Science of Psychedelics Teaches Us About Consciousness, Dying, Addiction, Depression, and Transcendence.
Obesity has reached alarming levels in Thailand, which ranks as the second-heaviest nation in Asia, after Malaysia. One in three Thai men are obese, while more than 40 percent of women are significantly overweight, according to Thailand’s national health examination survey.
Monks are at the forefront of the problem. Nearly half are obese, according to a study conducted by Chulalongkorn University. More than 40 percent have high cholesterol, nearly 25 percent have high blood pressure and one in 10 are diabetic, the study found.
That is from Mukita Suhartono at the NYT.
Where are most airplanes fixed? In foreign countries where the price of skilled labor is lower than in the United States.
US Airways and Southwest fly planes to a maintenance facility in El Salvador. Delta sends planes to Mexico. United uses a shop in China. American still does much of its most intensive maintenance in-house in the U.S., but that is likely to change in the aftermath of the company’s merger with US Airways.
Vanity Fair had a piece on this “Disturbing Truth” a few years ago. The VF piece presents a few anecdotes of safety violations at foreign maintenance facilities to stoke up fear. Naturally, no comparison to safety violations at US maintenance facilities is given. More serious data doesn’t bear out the worries of Vanity Fair. Worldwide airline safety is at an all time-high. Consider this amusing bit:
Even engine repairs and overhaul—the highly skilled aircraft-maintenance work that has remained largely in the U.S. and Europe—may follow heavy maintenance to the developing world. Emirates, the airline owned by the Gulf states, is constructing a $120 million state-of-the-art engine-repair-and-overhaul facility in Dubai.
Amusing because the world’s safest airline according to the German JACDEC (Jet Airliner Crash Data Evaluation Centre) is Emirates based in Dubai. Etihad the UAE’s second largest airline follows up closely. Chinese and South American airlines such as Sichuan Air score above most US airlines and Avianca, the El Salvador-Columbia airline, also scores highly. Of course, crashes are so rare that none of these rankings should be taken very seriously except in the sense that all of these airlines are very safe. Thus, I don’t worry much about where maintenance occurs. Indeed, if maintenance can be done for less we ought to buy more, so less expensive can mean safer.
Rather than fearing the offshoring of airplane maintenance we ought to ask how we can expand the concept. Medical tourism, for example, is growing. If foreign airplane maintenance is good enough for Delta then foreign human maintenance is good enough for me. Why don’t more US health insurance companies pay for medical procedures performed abroad? If a major medical insurer started to test and rate foreign providers and count some of them as in-service this could great alleviate fear increasing demand, lower costs, and put price pressure on US providers. Of course, we could also let in more foreign trained physicians and airplane mechanics.
Hat tip: Connor.
That is a new paper by Mikko Packalen and Jay Bhattacharya, here is the abstract:
The National Institutes of Health (NIH) plays a critical role in funding scientific endeavors in biomedicine that would be difficult to finance via private sources. One important mandate of the NIH is to fund innovative science that tries out new ideas, but many have questioned the NIH’s ability to fulfill this aim. We examine whether the NIH succeeds in funding work that tries out novel ideas. We find that novel science is more often NIH funded than is less innovative science but this positive result comes with several caveats. First, despite the implementation of initiatives to support edge science, the preference for funding novel science is mostly limited to work that builds on novel basic science ideas; projects that build on novel clinical ideas are not favored by the NIH over projects that build on well-established clinical knowledge. Second, NIH’s general preference for funding work that builds on basic science ideas, regardless of its novelty or application area, is a large contributor to the overall positive link between novelty and NIH funding. If funding rates for work that builds on basic science ideas and work that builds on clinical ideas had been equal, NIH’s funding rates for novel and traditional science would have been the same. Third, NIH’s propensity to fund projects that build on the most recent advances has declined over the last several decades. Thus, in this regard NIH funding has become more conservative despite initiatives to increase funding for innovative projects.
In 2003, Johnson and Goldstein published what would become a famous paper in Science, Do Defaults Save Lives? The paper featured a graph which showed organ donor consent rates in opt-in countries versus those in opt-out countries. The graph is striking because it seems to suggest that a simple change in the default rule can create a massive change in organ donor rates and thus save thousands of lives.
The graph, however, does NOT show organ donor rates. It shows that in opt-in countries few people explicitly opt-in and in presumed consent countries few people explicitly opt-out. But when a potential organ donor dies the families of people in opt-in countries who did not opt-in are still asked whether they would like to donate their loved one’s organs and many of them say yes. Similarly, in the presumed consent countries the families of people who did not opt-out are still typically asked whether they would like to donate their loved one’s organs and some of them say no.
The actual difference in organ donation rates between opt-in and presumed consent countries is much smaller than the differences in the graph, as Johnson and Goldstein made clear later in their paper. Nevertheless, the simple story in the graph encouraged many people to put excess weight on presumed consent as the solution to low organ donor rates.
The best estimates of presumed consent suggested that switching to presumed consent might increase organ donor rates by 25%. 25% isn’t bad! But we don’t have many examples of countries that have switched from one system to another so that estimate should be taken with a grain of salt.
The latest evidence comes form Wales which switched to presumed-consent in 2013. Unfortunately, there has been no increase in donation rates.
The most significant analysis of the new system is the Impact Evaluation Report, released by the Welsh Government in November 2017. Whilst focusing on the positives, such as increased understanding among medical staff, the report cannot escape the donation statistics, which clearly show no improvement. Covering the period from January 2010 or January 2011 to September 2017, all donation data show no change since the legislation’s introduction. The 21-month period before the Act came into effect saw 101 deceased donors, whereas the same period after showed 104; an increase, but one that can be properly attributed to expected annual fluctuation.
I still favor presumed consent or better, mandated choice, but I don’t think the binding constraints on organ donation are default rules. More important are preferences and fears about donation, the existence of a professional system using people who are trained to ask for donations, an institutional organization that can use donations when they are available (minimizing waste), and, of course, incentives.
Hat tip: Frank McCormick.
Here is the transcript and audio, I am very pleased (and honored) to have been able to do this. She is an autism researcher, and so most of the discussion concerned autism, here is one excerpt:
COWEN: What would be the best understanding of autism, from your perspective?
DAWSON: The best understanding is seeing autism as atypical brain functioning, resulting in atypical processing of all information. So that’s information across domains — social, nonsocial; across modalities — visual, auditory; whatever its source, whether it’s information from your memory, information coming from the outside world, that is atypical. So that is very domain-general atypicality.
What autistic brains do with information is atypical. How it’s atypical, in my view, involves what I’ve called cognitive versatility and less mandatory hierarchies in how the brain works, such that, for example, an autistic brain will consider more possibilities, will nonstrategically combine information across levels and scales without losing large parts of it, and so on. And that applies to all information.
That is strictly my view. I’m not sure anyone would agree with me.
COWEN: Now often, in popular discourse, you’ll hear autism or Asperger’s associated with a series of personality traits or features of personality psychology — a kind of introversion or people being nerdy in some regard. In your approach, do you see any connection between personality traits and autism at all?
DAWSON: There is a small literature that shows some connection. I think it’s very weak, and I say no, I don’t think autism is about personality. Autism is sort of orthogonal to personality. The two are not related. Whatever relation there is does not . . . arises from some third factor, let’s say. If there is one — and again, the evidence is, I think, very weak connecting autism to personality — so just say that maybe, if there’s something, let’s say that personality in autistics might be more high variance. That would be my totally wild guess, but I don’t think autism itself is about personality.
And here is Michelle again:
We don’t — I hope we don’t look at a blind person who is a successful lawyer and assume that he is only very mildly blind or barely blind at all, and then look at a blind person who has a very bad outcome and assume that they must be very severely blind.
We do make those kinds of judgments in autism, saying, “The more atypical the person is, the worse they must be in some sense.” That kind of bias has not only harmed a lot of autistic people, it really has impeded research.
Here is Michelle on Twitter. We discuss and link to some of her research in the discussion.
A 63-nation survey funded by WHO and the Bill & Melinda Gates Foundation found anywhere from 6 to 11 percent of new infections involved drug-resistant forms of HIV, and the trend was dire, with resistance increasing as high as 23 percent annually. Once individuals were put on their daily treatments, in 2017 failure rates due to drug resistance were as high as 90 percent in some countries, meaning new infections in those regions could no longer be controlled with the $75-a-year first-line therapies. The first such survey conducted in Cameroon, recently published, found that the majority of patients failing their primary treatments—up to 88 percent of them—were infected with resistant strains of HIV, and overall drug resistance rates in the West African nation in 2018 approach 18 percent.
Meanwhile, preventing HIV infection has fallen off the priority list, both in funding and individual action.
There is more of interest at the link, that is from Laurie Garrett, writing at Foreign Policy.
For the time being, we have turned off comments on MR posts. Is not a higher gdp a good thing?
1. In 1800, there were no formal laws against abortion in the United States, although common law suggested that the fetus had rights after a process of “quickening.”
2. Ten states passed anti-abortion laws in the 1821-1841 period. De facto there were many exceptions and enforcement was loose.
3. Abortion became a fully commercialized business in the 1840s, and this led to more public discussion of the practice. Abortion in fact became one of the first medical specialties in American history. It is believed that abortion rates jumped over the 1840-1870 period, and mostly due to married women.
4. Drug companies started to supply their own abortion “remedies” in the 1840s on a much larger scale.
5. At this time there were few moral dilemmas, at least not publicly expressed, about the termination of pregnancies in the earlier stages. That came later in the 20th century.
6. In 1878, a group of physicians in Illinois estimated the general abortion rate at 25%. In any case during this time period abortion was affordable to many more Americans than just the wealthy.
7. Several states started to criminalize abortion during the 1850s.
8. 1857-1880 saw the beginning of a physicians’ crusade against abortion. By 1880, abortion was illegal in most of the United States, and this occurred part and parcel with a rise in the professionalization of the medical profession. These policies were later sustained and extended throughout the 1880s and also the early twentieth century.
9. Over the 1860-1880 period, doctors succeeded in turning American public opinion significantly against abortion. The homeopaths supported them in this.
This is all from the very useful and readable book Abortion in America: The Origins and Evolution of National Policy, by James C. Mohr.
On average, patients get about 11 seconds to explain the reasons for their visit before they are interrupted by their doctors. Also, only one in three doctors provides their patients with adequate opportunity to describe their situation…
In just over one third of the time (36 per cent), patients were able to put their agendas first. But patients who did get the chance to list their ailments were still interrupted seven out of every ten times, on average within 11 seconds of them starting to speak. In this study, patients who were not interrupted completed their opening statements within about six seconds.
Now solve for the telemedicine equilibrium.
Scientific output is not a linear function of amounts of federal grant support to individual investigators. As funding per investigator increases beyond a certain point, productivity decreases. This study reports that such diminishing marginal returns also apply for National Institutes of Health (NIH) research project grant funding to institutions. Analyses of data (2006-2015) for a representative cross-section of institutions, whose amounts of funding ranged from $3 million to $440 million per year, revealed robust inverse correlations between funding (per institution, per award, per investigator) and scientific output (publication productivity and citation impact productivity). Interestingly, prestigious institutions had on average 65% higher grant application success rates and 50% larger award sizes, whereas less-prestigious institutions produced 65% more publications and had a 35% higher citation impact per dollar of funding. These findings suggest that implicit biases and social prestige mechanisms (e.g., the Matthew effect) have a powerful impact on where NIH grant dollars go and the net return on taxpayers investments. They support evidence-based changes in funding policy geared towards a more equitable, more diverse and more productive distribution of federal support for scientific research. Success rate/productivity metrics developed for this study provide an impartial, empirically based mechanism to do so.
Simplifiers give one a better overall picture of how the world works, whereas constructors are trying to build something. The balance seems to be shifting, for instance in physics:
Within the Physics label…we find the simplifiers dominated three quarters of the Nobel Prizes from 1952 to 1981, but more recently constructors have edged the balance with more than half of those from 1982 to 2011.
There is also a shift toward constructors in chemistry, though it is less abrupt. In the fields of physiology and medicine, however, simplifiers reign supreme and there has been no shift across time. Three-quarters of the prizes are still going to simplifiers.
Does that mean we should be relatively bullish about progress in those areas, based on forthcoming fundamental breakthroughs?
All these points are from Jeremy J. Baumberg’s new and interesting The Secret Life of Science: How It Really Works and Why It Matters.