The GiveWell Blog

Geomagnetic storms: Using extreme value theory to gauge the risk

(updated on: ) | by David Roodman

This is the third post in a series about geomagnetic storms as a global catastrophic risk. A paper covering the material in this series was just released.

My last post examined the strength of certain major geomagnetic storms that occurred before the advent of the modern electrical grid, as well as a solar event in 2012 that could have caused a major storm on earth if it had happened a few weeks earlier or later. I concluded that the observed worst cases over the last 150+ years are probably not more than twice as intense as the major storms that have happened since modern grids were built, notably the storms of 1982, 1989, and 2003.

But that analysis was in a sense informal. Using a branch of statistics called Extreme Value Theory (EVT), we can look more systematically at what the historical record tells us about the future. The method is not magic—it cannot reliably divine the scale of a 1000-year storm from 10 years of data—but through the familiar language of probability and confidence intervals it can discipline extrapolations with appropriate doses of uncertainty. This post brings EVT to geomagnetic storms.

For intuition about EVT, consider the storm-time disturbance (Dst) index introduced in the last post, which represents the average depression in the magnetic field near the equator. You can download the Dst for every hour since 1957: half a million data points and counting. I took this data set, split it randomly into some 5,000 groups of 100 data points, averaged each group, and then graphed the results. Knowing nothing about the distribution of hourly Dst—does it follow a bell curve, or have two humps, or drop sharply below some threshold, or a have long left tail?—I was nevertheless confident that the averages of random groups of 100 values would approximate a bell curve. A cornerstone of statistics, the Central Limit Theorem, says this will happen. Whenever you hear a pollster quote margins of error, she is banking on the Central Limit Theorem.

Key questions about philanthropy, part 2: Choosing focus areas and hiring program staff

(updated on: ) | by Holden

This post is second in a series on fundamental questions about philanthropy that we’ve grappled with in starting a grantmaking organization (see link for the series intro). In this post, we discuss the following questions:

  • Should a funder set explicit focus areas, and if so, how should they choose the focus areas? We believe it generally makes sense to declare focus areas (i.e., causes that one plans to focus on). While it’s common for philanthropists to choose focus areas based on preexisting personal passions, we are taking a different approach. This choice is arguably the most important a funder makes, and we are trying to be strategic about it. More
  • How many focus areas should one work in? We’re highly undecided about this question. We see most funders working in relatively few focus areas, with a high level of depth and expertise. But we also see some appeal in the idea of pursuing more breadth at the cost of depth. More
  • What does a program staffer do on a day-to-day basis? We use the term “program staff” to refer to the staff who have primary responsibility for finding and evaluating giving opportunities (though not necessarily making the final grant decision). One clear part of their role is checking in on existing grants. But it’s less obvious what the most effective activities are for finding new giving opportunities. Our sense is that the most valuable activities include articulating and refining one’s grantmaking priorities, as well as networking. It strikes us that these activities may often lead to higher returns than running an open-ended grant application process. More
  • What sort of person makes a good program staffer? We are still forming our views on this question. Some qualities we think are generally important include strong alignment and communication with the people who will ultimately be responsible for grantmaking decisions (e.g., any executives and funders working with the program staffers); a strong sense of one’s strengths and weaknesses; and strong interpersonal skills. More

Has violence declined, when large-scale atrocities are systematically included?

(updated on: ) | by Holden

Note: I wrote the following on my personal time, then cleaned it up slightly for public consumption. This post is not directly related to GiveWell’s work, but we thought readers might find it interesting anyway. It provides a simple supplementary analysis to the argument presented in The Better Angels Of Our Nature that violence has declined over time. I conclude that the book’s big-picture point stands overall, but my analysis complicates the picture, implying that declines in deaths from everyday violence have been significantly (though probably not fully) offset by higher risks of large-scale, extreme sources of violence such as world wars and oppressive regimes.

Thanks to Steven Pinker for reviewing a draft of this post.

One of my favorite nonfiction books is The Better Angels of our Nature by Steven Pinker. It argues that “violence has declined over long stretches of time, and today we may be living in the most peaceable era in our species’ existence … it is an unmistakable development, visible on scales from millennia to years, from the waging of wars to the spanking of children.” For the most part, I think the book is quite convincing on this point.

This post focuses on what I see as the biggest missing piece of its analysis. The major large-scale atrocities of the 20th century – particularly the two World Wars and the regimes of Josef Stalin and Mao Zedong – stand as an obvious challenge to the book’s theme of declining violence over time. Better Angels does address these events, arguing that they are not as historically anomalous as they may seem. However, the book does not give a comprehensive, quantified picture of how recent centuries compare to older ones in terms of total deaths from such large-scale atrocities. It also does not compare the relative death toll of large-scale atrocities to that of other sources of violent deaths it discusses (homicide, witch hunts, executions, etc.) to determine whether the atrocities of the 20th century were violent enough to offset other kinds of improvements. While many critics have highlighted the atrocities of the 20th century, I don’t believe any of them have done this sort of analysis either, with the exception of a partial analysis on the Uncommon Descent blog.

Using some of the data cited in Better Angels, I’ve done a simple analysis to lay out estimated “deaths from major atrocities” for each century, going back to the 5th century BC. I’ve also looked a bit into how these figures would look if we included deaths from everyday violence as well. Having done this, four points stand out:

  • There are two other centuries (13th and 17th) that look to have been at least as bloody as the 20th, though this observation is very sensitive to very imprecise death toll estimates of a very small number of atrocities. (“Bloody” here refers to high violent deaths per capita per year; “atrocity” means an enormous large-scale mass killing, like a war or conquest or democide.) The 13th century death toll comes almost entirely from estimates of the damage done by Genghis Khan, while the 17th century death toll comes mostly from estimates about the fall of the Ming Dynasty. I don’t see a clear trend overall on “death risk from large-scale atrocities” from the 13th through 20th centuries.
  • Prior to the 13th century, it looks like per-century death tolls from the largest atrocities were consistently lower, and I doubt that this is an artifact of the data.
  • Around the 15th century, a documented fall in the homicide rate seems to have started. The homicide rate decline and the rise in deaths from very large-scale atrocities that took place between the 13th and 15th centuries seem to be in the same ballpark as each other, consistent with the idea that violence shifted from individuals to regimes. I would guess that the net effect was a decline in violent deaths, especially when bearing certain issues with the data in mind, but it isn’t clear.
  • Large-scale atrocities account for enormous numbers of violent deaths. While Better Angels describes multiple trends, it does not compare them to each other in an apples-to-apples way. My sense is that large-scale atrocities account for far more violent deaths than most of the other sources of violence the book discusses – so the lack of a positive trend means that the overall global risk of dying from violence may not have improved greatly over time (though it probably has improved). To make this point vivid, the global rate of violent deaths from the “big four” atrocities alone (two World Wars, regimes of Josef Stalin and Mao Zedong) – spread out over the entire 20th century – is ~50 violent deaths per 100,000 people per year; that’s comparable to the very worst national homicide rates seen today, whereas the homicide rate for high-income countries such as the U.S. tends to be less than 1/10 as high. In other words, the two World Wars + Stalin and Mao alone were enough to make the 20th century as a whole more dangerous than homicide makes today’s homicide-heaviest countries, and they were enough to offset the benefit of the European homicide rate decline that Better Angels describes from Medieval times through the Enlightenment.

Looking purely at quantified violent death risk by century, the picture that emerges from these figures is one of falling everyday violence that is significantly (though probably not fully) offset by higher risks of large-scale, extreme sources of violence such as world wars and oppressive regimes. The net impact is probably lower levels of violence, but it’s not entirely clear. The key transition looks like it was around the 13th-15th centuries; I don’t see much reason to think that the Scientific Revolution should bear much blame for rising atrocity tolls (the timing doesn’t work), but the “rule of law and rising power of governments” dynamic that Better Angels credits for much of the decline in everyday violence could be argued to have had a significant cost in terms of rare mass atrocities.

The dynamics of violent deaths discussed above are consistent with a picture of modernization as improvement in everyday conditions, accompanied by larger rare catastrophic events. This picture can be applied to more recent times as well, even as death tolls from atrocities have fallen: everyday peacefulness has continued to improve, but the potential maximum damage of global catastrophic risks (such as power grid failures, natural and engineered pandemics, climate change and artificial intelligence) seems to be on the rise as well. Today, the potential bad news is even more unlikely and infrequent, but potentially even more enormous, than ever before.

Taking a more holistic view – looking at ways in which non-fatal violence has declined, the phenomenon of the “long peace” since the mid-20th century, and other improvements over time – I think it remains the case that the modern world has become greatly less violent, as well as a better place to live in other ways. I do think that the overall point of Better Angels stands with my analysis in mind, though there is some added complexity to it.

Finally, I note that the literature on this topic appears extremely thin. Steven Pinker is not a historian, yet I believe his systematic examination of historical trends in violence is the first of its kind. Many critics of Better Angels highlight the question of how 20th century atrocities compared to past atrocities. However, I’ve seen only one critic who did either of the following: (a) spelled out a more systematic comparison Pinker could have done; (b) performed a rough version of this comparison. This critic was Uncommon Descent, a blog whose main purpose appears to be arguing for Intelligent Design.

Details follow. From this point on I abbreviate Better Angels as BA.

  • I go through BA’s discussion of the major atrocities of the 20th century, and discuss why I believe more analysis is called for. BA’s argument and the need for more analysis
  • I discuss my own rough attempt to make these comparisons, and what it shows: a lack of clear trend in deaths from large-scale atrocities from the 13th through 20th centuries, a smaller death toll from large atrocities but a higher toll from homicides prior to the 15th century, and the relative importance of large-scale atrocities vs. other sources of violence. More: My analysis
  • I reflect on how one should think about long-term historical trends in violence and quality of life with these corrections in mind. Reflections

Geomagnetic storms: History’s surprising, if tentative, reassurance

(updated on: ) | by David Roodman

This is the second post in a series about geomagnetic storms as a global catastrophic risk. A paper covering the material in this series was just released.

My last post raised the specter of a geomagnetic storm so strong it would black out electric power across continent-scale regions for months or years, triggering an economic and humanitarian disaster.

How likely is that? One relevant source of knowledge is the historical record of geomagnetic disturbances, which is what this post considers. In approaching the geomagnetic storm issue, I had read some alarming statements to the effect that global society is overdue for the geomagnetic “Big One.” So I was surprised to find reassurance in the past. In my view, the most worrying extrapolations from the historical record do not properly represent it.

I hasten to emphasize that this historical analysis is only part of the overall geomagnetic storm risk assessment. Many uncertainties should leave us uneasy, from our incomplete understanding of the sun to the historically novel reliance of today’s grid operators on satellites that are themselves vulnerable to space weather. And since the scientific record stretches back only 30–150 years (depending on the indicator) and big storms happen about once a decade, the sample is too small to support sure extrapolations of extremes.

Nevertheless the historical record and claims based on it are the focus in this and the next post. I’ll examine four (kinds of) extrapolations that have been made from the record: from the last “Big One,” the Carrington event of 1859; from the July 2012 coronal mass ejection (CME) that might have caused a storm as large if it had hit Earth; a more complex extrapolation in Kappenman (2010); and the formal statistical extrapolation of Riley (2012). I’ll save the last for the next post.

Geomagnetic storms: An introduction to the risk

(updated on: ) | by David Roodman

Image from NASA via Wikipedia
This is the first post in a series about geomagnetic storms as a global catastrophic risk. A paper covering the material in this series was recently released.

The Open Philanthropy Project has included geomagnetic storms in its list of global catastrophic risks of potential focus.

To be honest, I hadn’t heard of them either. But when I was consulting for GiveWell last fall, program officer Howie Lempel asked me to investigate the risks they pose. (Now I’m an employee of GiveWell.)

It turns out that geomagnetic storms are caused by cataclysms on the sun, which fling magnetically charged matter toward earth. The collisions can rattle earth’s magnetic field, sending power surges through electrical grids. The high-speed particles can also take out satellites critical for communication and navigation. The main fear is that an extreme storm would so damage electrical grids as to black out power on a continental scale for months, even years. The toll of such a disaster would be tallied in economic terms, presumably in the trillions of dollars. It would also be measured in lives lost, since all the essential infrastructure of civilization, from food transport to law enforcement, now depends on being able to plug things in and turn them on (NRC 2008, pp. 11–12).

Having examined the issue, especially its statistical aspects, I am not convinced that this scenario is as likely as some prominent voices have suggested. For example, as I will explain in a later post, Riley’s (2012) oft-cited estimate that an extreme storm—stronger than any since the advent of the modern grid—has a 12%-per-decade probability looks like an unrepresentative extrapolation from the historical record. I put the odds lower. My full report has just been posted, along with data, code, and spreadsheets.

Nevertheless, my reassurance is layered in uncertainty. The historical scientific record is short–we get a big storm about once a decade, and good data have only been collected for 30–150 years depending on the indicator. Scientific understanding of solar dynamics is limited. Likewise for the response of grids to storms. My understanding of the state of knowledge is itself limited. On balance, significant “tail risk”—of events extreme enough to cause great suffering—should not be ruled out.

This is why I think the geomagnetic storm risk, even if overestimated by some, deserves more attention from governments than it is receiving. To date, the attention has been minimal relative to the stakes.

The rest of this post delineates how geomagnetic storms come about and why they may particularly threaten one critical component of modern electrical grids, the high-voltage transformer. Later posts will delve into what the available evidence says about the chance of a geomagnetic “perfect storm.”

Key questions about philanthropy, part 1: What is the role of a funder?

(updated on: ) | by Holden

This post was updated on July 6 with language edits but substantially unchanged content.

As a new funder, we’ve found it surprisingly difficult to “learn the ropes” of philanthropy. We’ve found relatively little reading material – public or private – on some of the key questions we’re grappling with in starting a grantmaking organization, such as “What sorts of people should staff a foundation?” and “What makes a good grant?” To be sure, there is some written advice on philanthropy, but it leaves many of these foundational questions unaddressed.

As we’ve worked on the Open Philanthropy Project, we’ve accumulated a list of questions and opinions piecemeal. This blog post is the first in a series that aims to share what we’ve gathered so far. We’ll outline some of the most important questions we’ve grappled with, and we’ll give our working answer for each one, partly to help clarify what the question means, and partly to record our thoughts, which we hope will make it easier to get feedback and track our evolution over time.

We’d love to see others – particularly experienced philanthropists – write more about how they’ve thought through these questions, and other key questions we’ve neglected to raise. We hope that some day new philanthropists will be able to easily get a sense for the range of opinions among experienced funders, so that they can make informed decisions about what kind of philanthropist they want to be, rather than starting largely from scratch.

This post focuses on the question: “what is the role of a funder, relative to other organizations?” In brief:

  • At first glance, it seems like a funder’s main comparative advantage is providing funding, and one might guess that a funder would do well to stick to this role as closely as possible. In other words, a funder might seek to play a ”passive” role, by considering others’ ideas and choosing which ones to fund, without trying to actively influence what partner organizations work on or how they work on it.
  • In practice, this doesn’t seem to be how the vast majority of major funders operate. It’s common for funders to develop their own strategies, provide funding restricted for specific purposes, develop ideas for new organizations and pitch them to potential founders, and more. Below, we lay out a spectrum from “highly passive” funders (focused on supporting others’ ideas) to “highly active” funders (focused on executing their own strategies, with strong oversight of grantees). More
  • In the final section of this post, we lay out our rough take on when we think it’s appropriate for us, as a funder, to do more than write a check. In addition to some roles that may be familiar from for-profit investing – such as providing connections, helping with fundraising and providing basic oversight – we believe it is also worth noting the role of funders play via cause selection, and the role a funder can play in filling gaps in a field by creating organizations. More