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Updating My Risk Estimate for the Geomagnetic “Big One”

In 2015, I researched and wrote about the risk to industrial society from geomagnetic storms—terrestrial phenomena that, despite their name, originate on the sun. Mild storms give us the ineffable beauty of the Northern Lights, and the Southern Lights too. Severe geomagnetic maelstroms might, some fear, knock out key satellites or cause continent-wide blackouts that would take months to undo.

I concluded that the risk had been exaggerated in the studies that gained the most attention. Still, given the potential stakes and the historical neglect of the problem, the issue deserved more attention from people in science, business, and government.

As I wrapped up my investigation, I tripped on a question of statistical method that I did not have time to fully explore. I have since put more time into the question. I just finalized a working paper about the results and submitted it to a journal. The upshot for the geomagnetic storm investigation is that I have modified my methods for extrapolating storm risks from the historical record. As a result, I have raised my best estimate of the chance of a really big storm, like the storied one of 1859, from 0.33% to 0.70% per decade. And I have expanded my 95% confidence interval for this estimate from 0.0–4.0% to 0.0–11.6% per decade.

More explanation follows.

Maybe the Murder Rate Levelled Off This Year?

In February, out of concern that the US is experiencing a new crime wave, I blogged about a data set Open Phil assembled on crime in major American cities. In comparison with the FBI’s widely cited national totals, our data covered far less territory—18 cities for which we found daily incident data—but did better in the time dimension, with higher resolution and more up-to-date counts. We could compute daily totals, and from data sets that for many cities are almost literally up-to-the-minute.

Some places that have recently made national crime news also appear in our data, including Baltimore, Chicago, St. Louis, and Washington, DC. Within our geographic scope, we gain a better view into the latest trends than we can get from the FBI’s annual totals, which appear with a long lag.

Indeed the FBI will probably release its 2015 crime totals in the next few days, which may stoke discussion about crime in the US. [Update: it just did].

In this post, I update all the graphs presented in the earlier one, which I suggest you read first. These updates generate predictions about what the FBI will announce, and perhaps point to one trend that it won’t yet discern.

With 8 more months of data on these 18 cities, plus the addition of New York for 2006–15, the main updates on per-capita crime rates are:

  • On a population-weighted basis, the hints in the old post of decline at the end of 2015, in violent crime in general and homicide in particular, have faded—or at least have been pushed forward in time.
  • Instead, after the homicide rise of late 2014 and 2015—which indeed was one of the largest increases in modern times—the homicide trend has flattened.
  • Violent crime rose slowly, as it has since mid-2014. It remains low historically, down roughly a third since 2001.
  • Property crime (burglary, theft, arson) continues to sink like a stone.

If our data capture national trends (which is far from certain), then the FBI will soon report that the 2015 homicide rate rose a lot from 2014, that violent crime rose a little bit, that property crime fell, and that total crime, which is dominated in sheer quantity by property crime, also fell. [Update: these look right.]

Here are the Open Phil graphs, updated through a few weeks ago and starting with homicide (data and code here):

Homicide-pop.png

America’s Recently Heralded Urban “Crime Wave” May Already Have Peaked

Writing in the Wall Street Journal last May, the Manhattan Institute’s Heather Mac Donald blackly heralded a “new nationwide crime wave.” She blamed the “Ferguson effect”: a pull-back by police in the face of public hostility over alleged abuses. Ferguson, of course, is the city in St. Louis county where in August 2014, a police officer shot and killed Michael Brown, leading to days of rioting.

Toward the end of last summer, two reporters at the New York Times chimed in on the existence of an uptick, at least in homicide: “Murder Rates Rising Sharply in Many U.S. Cities.”

These suggestions of an incipient crime wave caught Open Phil’s attention because we are entering the field of criminal justice reform. Might attempts to curb the “tough-on-crime” approach that has made the United States the world’s greatest prison state backfire in the form of higher crime? Or if not, might fear of such obstruct reform?

As the crime wave meme spread, it provoked counterreactions: Joseph Margulies on “The Dangerous Notion of a Nationwide Crime Wave”; Richard Rosenfeld of St. Louis University questioning whether even St. Louis felt the Ferguson effect; FiveThirtyEight’s Carl Bialik on how “Scare Headlines Exaggerated The U.S. Crime Wave”; a Brennan Center report and a New York Times editorial it inspired; and end-of-year updates by Radley Balko for the Washington Post and Thomas Abt for the Marshall Project.

Here, I present my attempt, with the help of GiveWell’s Jake Marcus, to sort out the controversy of whether America is experiencing a crime wave. Our results are all graphical. Our analysis is distinctive in starting from daily data rather than monthly or yearly totals, which I find a bit coarse when examining trends over just the last year or so.

But, as with the other articles and posts, our numbers are not definitive. We obtained high-frequency data—lists of individual crimes—for 19 major municipalities. The statistics pertain only to territories within city limits, not to broader metropolitan areas. Even if they did, the sampled cities may not be representative of all cities, let alone the entire United States.

Nevertheless, the results look reasonable and interesting. In our sample, the murder rate does rise starting around January 2014. But this fluctuation so far looks small compared to the big, overall slide since 2001, and is commensurate with past, temporary reversals. And it may have peaked a few months ago. (You heard it here first.) Meanwhile, totals for the broader category of violent crime, in which the rare offense of homicide hardly figures, rose only slightly, even as property crime kept dropping. These splits across crime types are the opposite of what I would expect from a Ferguson effect. Seemingly, more than with crimes of passion, theft and burglary begin with rational consideration of risk factors such as whether the police are around. But they kept falling.

Zeroing in on the conceptual boundary within violent crime between homicide and everything else, we find that the crime subtype most resembling murder—armed assault—also appears to have ticked upward, especially if we restrict to assault with a firearm. It may be then the recent crime wave is best seen as a gun crime wave. We are not certain, in part because data limitations force us to base that finding on just nine cities. And, in an even smaller sample, non-gun homicides have recently climbed faster than gun homicides.

As the FBI gathers comprehensive statistics this year, the reality of last year will become clearer.

Why a New Study of the Mariel Boatlift Has Not Changed Our Views on the Benefits of Immigration

Note: Before the launch of the Open Philanthropy Project Blog, this post appeared on the GiveWell Blog. Uses of “we” and “our” in the below post may refer to the Open Philanthropy Project or to GiveWell as an organization. Additional comments may be available at the original post.

Mariel_Refugees[1]

As a consultant for the Open Philanthropy Project last year, I reviewed the research on whether immigration reduces employment or earnings for workers in receiving countries. I concluded that for natives the harm, if any, is small.

Last month the prominent immigration researcher George Borjas posted a challenge to a seminal study in my review. His new paper contends that the Mariel boatlift, which brought some 60,000 Cuban refugees to Miami in 1980, did profoundly affect the labor market there, depressing wages for low-education men (ones with less than a high school education) by 10–30%.

Borjas’s work is especially significant because it seems to upend a study of the boatlift published by David Card 25 years ago, which found little impact of all that immigration on workers in Miami. Interestingly, Borjas, who emphasizes the harm of Cuban immigration, is himself a Cuban emigré.

I probed this dispute, replicating and checking the results in the dueling papers. I ultimately found little cause to change my views. The main reasons:

  • Of the two Census Bureau data sets that Borjas relies on, the one with larger samples shows smaller impacts.
  • According to that data set, wages for women, which Borjas excludes, rose, if anything, after immigration spikes (especially after a second one in 1994–95).
  • I see no sharp breaks from long-term trends of the sort that could be confidently attributed to the 1980 immigration surge. The Borjas analysis appears correct that wages for low-education Miami men (defined henceforth as those with less than a high school education) were lower on average in 1981–83 than in 1977–79—with the drop being larger than in most other US cities. But the data argue more for a steady long-term decline than sudden drops after immigration surges. The Borjas analysis tends to obscure this distinction by aggregating or smoothing data over several years.
  • The original study by David Card is one of 17 covered in my review, including three others exploiting natural experiments in mass migration. None of the studies is as compelling as a randomized trial, but the overall picture—of at most modest harm from substantial immigration—does not change if the Card study is removed.

Details follow.

Coming Down to Earth: What if a Big Geomagnetic Storm Does Hit?

Note: Before the launch of the Open Philanthropy Project Blog, this post appeared on the GiveWell Blog. Uses of “we” and “our” in the below post may refer to the Open Philanthropy Project or to GiveWell as an organization. Additional comments may be available at the original post.

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

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