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The NYTimes on the FDA and Rapid Tests

In July of 2020 I wrote in Frequent, Fast, and Cheap is Better than Sensitive:

A number of firms have developed cheap, paper-strip tests for coronavirus that report results at-home in about 15 minutes but they have yet to be approved for use by the FDA because the FDA appears to be demanding that all tests reach accuracy levels similar to the PCR test. This is another deadly FDA mistake.

…The PCR tests can discover virus at significantly lower concentration levels than the cheap tests but that extra sensitivity doesn’t matter much in practice. Why not? First, at the lowest levels that the PCR test can detect, the person tested probably isn’t infectious. The cheap test is better at telling whether you are infectious than whether you are infected but the former is what we need to know to open schools and workplaces.

It’s great that other people including the NYTimes are now understanding the problem. Here is the excellent David Leonhardt in Where are the Tests?

Other experts are also criticizing the Biden administration for its failure to expand rapid testing. Even as President Biden has followed a Covid policy much better aligned with scientific evidence than Donald Trump’s, Biden has not broken through some of the bureaucratic rigidity that has hampered the U.S. virus response.

In the case of rapid tests, the F.D.A. has loosened its rules somewhat over the past year, allowing the sale of some antigen tests (which often cost about $12 each). But drugstores, Amazon and other sellers have now largely run out of them. I tried to buy rapid tests this weekend and couldn’t find any.

The F.D.A.’s process for approving rapid tests is “onerous” and “inappropriate,” Daniel Oran and Dr. Eric Topol of Scripps Research wrote in Stat News.

For the most part, the F.D.A. still uses the same cumbersome process for approving Covid tests that it uses for high-tech medical devices. To survive that process, the rapid tests must demonstrate that they are nearly as sensitive as P.C.R. tests, which they are not.

But rapid tests do not need to be so sensitive to be effective, experts point out. P.C.R. tests often identify small amounts of the Covid virus in people who had been infected weeks earlier and are no longer contagious. Rapid tests can miss these cases while still identifying about 98 percent of cases in which a person is infectious, according to Dr. Michael Mina, a Harvard epidemiologist who has been advocating for more testing

Identifying anywhere close to 98 percent of infectious cases would sharply curb Covid’s spread. An analysis in the journal Science Advances found that test frequency matters more for reducing Covid cases than test sensitivity.

As I said on twitter what makes the FDA’s failure to approve more rapid antigen tests especially galling is that some of the tests being sold cheaply in Europe are American tests just ones not approved in the United States. If it’s good enough for the Germans it’s good enough for me!

Two brutal tests — can you pass them?

We all give people “tests” when we meet them, whether we are consciously aware of it or not.  Here are two of mine:

1. The chess test.  When I played chess in my youth, I would commonly analyze games with other players.  You would then rapidly learn just how much and how quickly the other player could figure out the position and see imaginative variations.  Some players maybe had equal or even inferior results to mine (I had a good work ethic and took no drugs), but it was obvious they were greater talents at analysis.  Top chess players who worked with Bobby Fischer also attest that in this regard he was tops, not just “another great player.”  That was true even before he was good enough and steady enough to become world champion.

When talking ideas with people, the same issue surfaces — just how quickly and how imaginatively do they grasp what is going on?  You should put aside whatever they have or have not accomplished.  How much do they have this Bobby Fischer-like capacity to analyze?  No matter what their recent results have been (remember how Efim Geller used to kick Fischer’s butt in actual games?).

2. The art test.  Take a person’s favorite genres of art, music, whatever.  But something outside of their work lives.  Maybe it can even be sports.  How deeply do they understand the said subject matter?  At what kind of level can they talk about it or enjoy it or maybe even practice it?

Remember in Hamlet, how Hamlet puts on a play right before the King’s eyes, to see how the King reacts to “art”?

Here we are testing for sensibility more than any kind of rigorous analysis, though the analysis test may kick in as well.  Just how deep is the person’s deepest sensibility?

If you are investing in talent, you probably would prefer someone really good at one of these tests over someone who is “pretty good” at both of them.

3. All other tests.

Now, people can be very successful while failing both “the chess test” and “the art test.”  In fact, most successful people fail both of these tests.  Still, their kinds of success will be circumscribed.  They are more likely to be hard-working, super-sharp, and accomplished, perhaps charismatic as well, while lacking depth and imaginative faculty in their work.

Nonetheless they will be super-focused on being successful.

I call this the success test.

Now if someone can pass the chess test, the art test, and the success test with flying colors…there are such people!

And if the person doesn’t pass any of those tests, they still might be just fine, but there will be a definite upper cap on their performance.

Update on Rapid Tests for COVID

Nearly a year ago, I wrote Frequent, Fast, and Cheap is Better than Sensitive, arguing for rapid antigen tests:

A number of firms have developed cheap, paper-strip tests for coronavirus that report results at-home in about 15 minutes but they have yet to be approved for use by the FDA because the FDA appears to be demanding that all tests reach accuracy levels similar to the PCR test. This is another deadly FDA mistake.

See also my posts Infected versus Infectious and Rapid Tests. The EMA and then the FDA finally did start approving these tests. So how well are they working? Pretty damn well. Canada has two innovative programs. First, in Nova Scotia pop-up clinics have been using rapid tests for asymptomatic people:

During the third wave that hit Nova Scotia over the past month, the province’s community rapid testing centres have correctly sniffed out at least 285 COVID-19 cases in asymptomatic people, or about 10 per cent of all confirmed cases in this time period, according to the Nova Scotia Health Authority.

While most provinces reserve testing only for symptomatic people or close contacts of a case, Nova Scotia’s pop-up centres allow asymptomatic people to simply show up and get a rapid test for free, with results sent to them within an hour. The whole process relies largely on volunteers without a health-care background.

Furthermore, the true number of cases credited to rapid testing is probably much higher. When a rapid test correctly identifies a positive case, the person’s close contacts such as their family get PCR lab tests that don’t show up in the rapid test statistics.

Lisa Barrett, an infectious diseases specialist and the driving force behind the rapid testing program, said it’s hard to say for certain, but taken altogether it’s possible rapid antigen testing has helped Nova Scotia find up to 18 per cent of all cases during the third wave.

“This is the early detection system,” Barrett said. Rapid testing tends to catch people early on in their infection when they’re full of virus, meaning positive cases are found and put into isolation fast — likely days before they would have been found with a PCR test, if they were found at all.

Michael Mina argues that since the rapid antigen detected cases are among the most infectious cases, detecting these cases is probably worth half of all the PCR testing.

Second, Canada’s CDL Rapid Screening Consortium is now in 200 sites with 50 large companies and rapidly expanding. A very interesting, just published paper in The Lancet runs an experiment that suggests that these testing regimes can work. The experiment rapidly tested 1000 people and the negatives were then randomly assigned either to be sent-home to conduct their regular life or to attend a multi-hour concert with masks but also singing, dancing, alcohol and no-social distancing. After 8 days there were two infections in the at-home group and no infections in the Concert group which suggests that this type of rapid testing can be used to open and keep-open concerts, schools, universities, airplanes and workplaces.

What’s the point of testing now that we have vaccines? Two reasons. First, most of the world still hasn’t been vaccinated so testing will be a very useful stop-gap measure until vaccination is more widely distributed. Indeed, the success of these programs shows what we lost by not acting more quickly a year ago. Second, although the pandemic is (essentially) over in the United States (as predicted) there will likely be an uptick in the fall among the unvaccinated and you want rapid tests to be available rapidly in hot-spots. In other words, rapid deployment of rapid tests will help us to avoid outbreaks in the future.

Rapid Antigen Tests in Canada

Josh Gans announces a program of Rapid Antigen Tests in Canada backed by a consortium of major Canadian companies.

Big News! Today I am very pleased to be able to reveal to the world something that I have been very proud to have been working on with a hundred or so other people: The CDL Rapid Screening Consortium. Led by our Creative Destruction Lab, this consortium is a group of 12 companies who are partnering with Health Canada to begin the roll-out of rapid antigen screens to be a part of daily life for the next 12-18 months and deliver a safer path to normality. We have been working since September intensively to put the consortium together, explore screening options that were available globally and come up with protocols and an evolving standard operating procedure (SOP) to bring rapid antigen screens at scale to economies all around the world. The goal is to solve the pandemic information gap and ensure that we can quickly identify and isolate infectious people and protect others.

The initial sites will be run by RSC members. Those members are Air Canada, Rogers, Loblaws, Shoppers Drug Mart, Magna, Nutrien, Suncor, Genpact, Scotiabank, MDA, CPPIB and MLSE.

Read Josh’s announcement for more details and here is the website for the CDL Rapid Screening Consortium.

Rapid Antigen Tests in Europe

Image‘If rapid antigen tests are so good how come other countries aren’t using them’? is a question I get asked a lot. In fact, India authorized these tests months ago. Slovakia tested most of their population using antigen tests. Germany is using them to protect nursing home residents. Lufthansa is trialing rapid antigen tests on special flights. Rapid antigen tests are now beginning to be available more widely in Europe. Here from a twitter thread is a picture of what they look like, it’s just a paper strip inside. You swab your nose (no need for deep cleaning), swirl the swab in a tube with some liquid and then squeeze a few drops of the liquid onto the end of the tester. Results in 15 minutes. They cost about $8 a test.

Why are these tests important? The CDC now says that asymptomatic or pre-symptomatic people account for a majority of infections. Do you get it? How many people without symptoms will get a COVID PCR test, which can be time consuming and expensive? (And how many PCR tests can we run in a timely fashion if people without symptoms get many more tests?) Not that many. But many people without symptoms would get a $8 or less, at-home, 15 minute test. And if some of those people discover that they are infectious and self-isolate for a few days we can drive infection rates down.

We should have had an Operation Warp Speed for tests. We still need funding for a mass rollout and, of course, the FDA needs to approve these tests! (Here is Michael Mina in Time fulminating at the FDA holdup.)

By the way, more than 2800 Americans have died of COVID since Pfizer requested an Emergency Use Authorization for their vaccine. The FDA meets Dec. 10.

Addendum: Here’s me explaining why Frequent, Fast, and Cheap is Better than Sensitive and the difference between infected and infectious.

Rapid Antigen Tests

Rapid antigen tests are starting to be adopted worldwide.

Reuters: Germany, where infections jumped by 4,122 on Tuesday to 329,453 total, has secured 9 million so-called antigen tests per month that can deliver a result in minutes and cost about 5 euros ($5.90) each. That would, in theory, cover more than 10% of the population.

The United States and Canada are also buying millions of tests, as is Italy, whose recent tender for 5 million tests attracted offers from 35 companies.

Germany’s Robert Koch Institute (RKI) now recommends antigen tests to complement existing molecular PCR tests, which have become the standard for assessing active infections but which have also suffered shortages as the pandemic overwhelmed laboratories and outstripped manufacturers’ production capacity.

See my earlier posts Frequent, Fast, and Cheap is Better than Sensitive, Infected versus Infectious, and Rapid Tests for more on these types of tests.

Rapid Tests

Here’s a good picture illustrating the difference between the PCR and Rapid Test. A PCR amplifies DNA and so if taken at the right time it will detect the virus before a rapid test will. But this happens when there isn’t much viral load and too little of the virus to be transmissible. Moreover, at these times, the virus is increasing rapidly so the rapid test will find the virus tomorrow. The PCR test will also pick up fragments after transmissiblity has passed which also isn’t very useful. A rapid test is very sensitive for doing what it is supposed to do, identifying periods of infectiousness.

Michael Mina has done a great job promoting rapid tests and I do think we are beginning to see some recognition of the difference between infected versus infectious and the importance of testing for the latter. What is frustrating is how long it has taken to get this point across. Paul Romer made all the key points in March! (Tyler and myself have also been pushing this view for a long time).

In particular, back in March, Paul showed that frequent was much more important than sensitive and he was calling for millions of tests a day. At the time, he was discounted for supposedly not focusing enough on false negatives, even though he showed that false negatives don’t matter very much for infection control. People also claimed that millions of tests a day was impossible (Reagents!, Swabs!, Bottlenecks!) and they weren’t impressed when Paul responded ‘throw some soft drink money at the problem and the market will solve it!’. Paul, however, has turned out be correct. We don’t have these tests yet but it is now clear that there is no technological or economic barrier to millions of tests a day.

Go yell at your member of Congress.

FDA Allows Pooled Tests and a Call for Prizes

The FDA has announced they will no longer forbid pooled testing:

In order to preserve testing resources, many developers are interested in performing their testing using a technique of “pooling” samples. This technique allows a lab to mix several samples together in a “batch” or pooled sample and then test the pooled sample with a diagnostic test. For example, four samples may be tested together, using only the resources needed for a single test. If the pooled sample is negative, it can be deduced that all patients were negative. If the pooled sample comes back positive, then each sample needs to be tested individually to find out which was positive.

…Today, the FDA is taking another step forward by updating templates for test developers that outline the validation expectations for these testing options to help facilitate the preparation, submission, and authorization under an Emergency Use Authorization (EUA).

This is good and will increase the effective number of tests by at least a factor of 2-3 and perhaps more.

In other news, Representative Beyer (D-VA), Representative Gonzalez (R-OH) and Paul Romer have an op-ed calling for more prizes for testing:

Offering a federal prize solves a critical part of that problem: laboratories lack the incentive and the funds for research and development of a rapid diagnostic test that will, in the best-case scenario, be rendered virtually unnecessary in a year.

…We believe in the ability of the American scientific community and economy to respond to the challenge presented by the coronavirus. Congress just has to give them the incentive.

The National Institutes of Health (NIH) have already begun a similar strategy with their $1.4 billion “shark tank,” awarding speedy regulatory approval to five companies that can produce these tests. Expanding the concept to academic labs through a National Institute of Science and Technology (NIST)-sponsored competition has the added benefit ultimately funding more groundbreaking research once the prize money has been awarded.

This is all good but frustrating. I made the case for prizes in Grand Innovation Prizes for Pandemics in March and Tyler and I have been pushing for pooled testing since late March. We were by no means the first to promote these ideas. I am grateful things are happening and relative to normal procedure I know this is fast but in pandemic time it is molasses slow.

It is better to do lots of tests, even if they are not entirely accurate

We find that the number of daily tests carried out is much more important than their sensitivity, for the success of a case-isolation based strategy.

Our results are based on a Susceptible-Exposed-Infectious-Recovered (SEIR) model, which is age-, testing-, quarantine- and hospitalisation-aware. This model has a number of parameters which we estimate from best-available UK data. We run the model with variations of these parameters – each of which represents a possible present state of circumstances in the UK – in order to test the robustness of our conclusion.

We implemented and investigated a number of potential exit strategies, focusing primarily on the effects of virus-testing based case isolation.

The implementation of our model is flexible and extensively commented, allowing us and others to investigate new policy ideas in a timely manner; we next aim to investigate the optimal use of the highly imperfect antibody tests that the United Kingdom already possesses in large numbers.

There is much more at the link, including the model, results, and source code.  That is from a team led by Gergo Bohner and also Gaurav Venkataraman, Gaurav being a previous Emergent Ventures winner.

Supply curves slope upward, Switzerland fact of the day, and how to get more tests done

Under Swiss law, every resident is required to purchase health insurance from one of several non-profit providers. Those on low incomes receive a subsidy for the cost of cover. As early as March 4, the federal health office announced that the cost of the test — CHF 180 ($189) — would be reimbursed for all policyholders.

Here is the article, that reimbursement is about 4x where U.S. levels had been.  The semi-good news is that the payments to Abbott are going up:

The U.S. government will nearly double the amount it pays hospitals and medical centers to run Abbott Laboratories’ large-scale coronavirus tests, an incentive to get the facilities to hire more technicians and expand testing that has fallen significantly short of the machines’ potential.

Abbott’s m2000 machines, which can process up to 1 million tests per week, haven’t been fully used because not enough technicians have been hired to run them, according to a person familiar with the matter.

In other words, we have policymakers who do not know that supply curves slope upwards (who ever might have taught them that?).

The same person who sent me that Swiss link also sends along this advice, which I will not further indent:

“As you know, there are 3 main venues for diagnostic tests in the U.S., which are:

1.       Centralized labs, dominated by Quest and LabCorp

2.       Labs at hospitals and large clinics

3.       Point-of-care tests

There is also the CDC, although my understanding is that its testing capacity is very limited.  There may be reliability issues with POC tests, because apparently the most accurate test is derived from sticking a cotton swab far down in a patient’s nasal cavity.  So I think this leaves centralized labs and hospital labs.  Centralized labs perform lots of diagnostic tests in the U.S. and my understanding is this occurs because of their inherent lower costs structures compared to hospital labs.  Hospital labs could conduct many diagnostic tests, but they choose not to because of their higher costs.

In this context, my assumption is that the relatively poor CMS reimbursement of COVID-19 tests of around $40 per test, means that only the centralized labs are able to test at volume and not lose money in the process.  Even in the case of centralized labs, they may have issues, because I don’t think they are set up to test deadly infection diseases at volume.  I’m guessing you read the NY Times article on New Jersey testing yesterday, and that made me aware that patients often sneeze when the cotton swab is inserted in their noses.  Thus, it may be difficult to extract samples from suspected COVID-19 patients in a typical lab setting.  This can be diligence easily by visiting a Quest or LabCorp facility.  Thus, additional cost may be required to set up the infrastructure (e.g., testing tents in the parking lot?) to perform the sample extraction.

Thus, if I were testing czar, which I obviously am not, I would recommend the following steps to substantially ramp up U.S. testing:

1.       Perform a rough and rapid diligence process lasting 2 or 3 days to validate the assumptions above and the approach described below, and specifically the $200 reimbursement number (see below).  Importantly, estimate the amount of unused COVID-19 testing capacity that currently exists in U.S. hospitals, but is not being used because of a shortage of kits/reagents and because of low reimbursement.  This number could be very low, very high or anywhere in between.  I suspect it is high to very high, but I’m not sure.

2.       Increase CMS reimbursement per COVID-19 tests from about $40 to about $200.  Explain to whomever is necessary to convince (CMS?…Congress?…) why this dramatic increase is necessary, i.e., to offset higher costs for reagents, etc. and to fund necessary improvements in testing infrastructure, facilities and personnel.  Explain that this increase is necessary so hospital labs to ramp up testing, and not lose money in the process.  Explain how $200 is similar to what some other countries are paying (e.g., Switzerland at $189)

3.       Make this higher reimbursement temporary, but through June 30, 2020. Hopefully testing expands by then, and whatever parties bring on additional testing by then have recouped their fixed costs.

4.       If necessary, justify the math, i.e., $200 per test, multiplied by roughly 1 or 2 million tests per day (roughly the target) x 75 days equals $15 to $30 billion, which is probably a bargain in the circumstances.

5.       Work with the centralized labs (e.g., Quest, LabCorp., etc.), hospitals and healthcare clinics and manufactures of testing equipment and reagents (e.g., ThermoFisher, Roche, Abbott, etc.) to hopefully accelerate the testing process.

6.       Try to get other payors (e.g., HMOs, PPOs, etc.) to follow CMS lead on reimbursement.  This should not be difficult as other payors often follow CMS lead.

Just my $0.02.”

TC again: Here is a Politico article on why testing growth has been slow.

FDA Stops At-Home Tests

TechCrunch…the U.S. Food and Drug Administration (FDA) has updated its Emergency Use Authorization guidelines to private labs that specifically bar the use of at-home sample collection. This means startups, including Everlywell, Carbon Health and Nurx, will have to immediately discontinue their testing programs in light of the clarified rules.

The FDA issued the updated guidance on March 21, and though some of the companies had already begun to ship their sample collection kits to people, and even begun to receive samples back to their diagnostic laboratory partners, even any samples in-hand will not be tested, and will instead be destroyed in order to comply with the FDA’s request

The tests are collected at home but the tests themselves are done in certified labs under quality-control standards (CLIA). It is of course possible, even likely, that tests collected at home are not as accurate as those collected by a trained nurse. But we don’t want trained nurses to be testing everyone–they have other things to do right now. Furthermore, some of these errors will be detected at the lab and can be fixed with a retest. False negatives are possible but going to a hospital or standing in line to get a test also comes with risk. False negatives will also become apparent to the extent that symptoms worsen at which time patients can seek medical assistance. Yes, of course, delay and false reassurance are also not without risk. Welcome to the world of tradeoffs. But at this point in time we need to unleash American ingenuity and enterprise and evolve our way to the frontier as conditions improve.

We need to learn now, regulate later.

Why are we letting FDA regulations limit our number of coronavirus tests?

Since CDC and FDA haven’t authorized public health or hospital labs to run the [coronavirus] tests, right now #CDC is the only place that can. So, screening has to be rationed. Our ability to detect secondary spread among people not directly tied to China travel is greatly limited.

That is from Scott Gottlieb, former commissioner of the FDA, and also from Scott:

#FDA and #CDC can allow more labs to run the RT-PCR tests starting with public health agencies. Big medical centers can also be authorized to run tests under EUA. For now they’re not permitted to run the tests, even though many labs can do so reliably 9/9 cdc.gov/coronavirus/20

Here is further information about the obstacles facing the rollout of testing.  And read here from a Harvard professor of epidemiology, and here.  Clicking around and reading I have found this a difficult matter to get to the bottom of.  Nonetheless no one disputes that America is not conducting many tests, and is not in a good position to scale up those tests rapidly, and some of those obstacles are regulatory.  Why oh why are we messing around with this one?

For the pointer I thank Ada.

How to think about the Chilean (and other) protests

That is the topic of my latest Bloomberg column, here is one excerpt:

Second, a protest against poor conditions is not the same as a protest against inequality. Many Chilean complaints revolve around the pension system, health care, water rights, public transportation, schools and corruption. Are Chileans upset that their transport options aren’t better? That’s a complaint in absolute terms. Or are they upset that they are riding the subway while many of the wealthy have private cars with drivers? That’s a relative complaint.

The answer will depend on the protester, and in virtually all protests around the world there will be those with both motives. But some North American commentators try to equate these two grudges and subsume them all under the heading of inequality. That just won’t wash.

And don’t forget this:

In the case of Chile, it has the highest real wages in Latin America, income inequality has mostly been falling, and life expectancy is above average for the region. By Latin American standards Chile has a low rate of crime and a high degree of public order. Chile has had open and honest elections, and peaceful transfers of power, since 1990.

So high expectations may be more relevant than either “inequality” or “neo-liberalism” per se, at least for many of the protestors.  There is much more of interest at the link, including some speculations as to why Chile may be different:

Another observation: Income inequality is often more galling when different economic classes encounter each other on a regular basis. So much Chilean economic and social activity is concentrated in Santiago, just as in South Korea it is in Seoul and in Singapore it is in … Singapore. In all three countries, I believe, feelings of inequality and envy are worse for that reason. By contrast, if you are a lower-middle-class person in, say, Mississippi, you may view the mansion and private plane of Bill Gates as if from a different universe.

I’ve also found Chile to have a relatively tough set of social expectations in terms of class, dress and educational background, and a relatively narrow set of expectations for women. These pressures for conformity may contribute to discontent.

Recommended.

What is behind the spread of so many mass protests?

One frequent theme is people objecting to a price increase. In Ecuador,  a focal point of the protests has been a demand for restoration of fuel subsidies. Petroleum price subsidies also have been central to the Haitian protests. In Lebanon, citizens have been upset at a new tax levied on the use of WhatsApp, with a social media tax also having been an issue in Uganda. In Sudan cuts to food and fuel subsidies have been a major complaint. In Chile they are protesting subway fare hikes.

The trend is that price increases may continue to become less popular. And, crucially, the internet will help people organize against such changes.

Consider that an old-style labor-oriented protest can be organized through the workplace or plant itself, through on-the-ground techniques that long predate the internet. There is a common locale and set of social networks in place, including perhaps a union. Those who suffer from a price increase, in contrast, typically do not know each other or have common social ties. Just about everyone buys gasoline, either directly or indirectly. The internet, however, makes it possible to mobilize these people into protests with prices as the common theme.

In other words: Protests of workers seem to be becoming less important, and protests of consumers are becoming more important.

You may recall that one of the original demands of the “gilets jaunes” protests in France was for free parking in Disneyland Paris. If you think that sounds a little crazy, you haven’t yet internalized the nature of the new millennium.

In the future, efficiency-enhancing or austerity-induced changes in prices may be much harder to accomplish politically. The new trend is neither central planning nor market liberal reforms, but rather frozen prices, especially when those prices are set in the political realm.

Here is the rest of my latest Bloomberg column on that topic.  Two further points: my global warming point I pulled from Noah Smith, though I could no longer find his tweet to cite. Furthermore, many of the recent protests, such as in Spain, fit a more political and ethnic model, I am not saying price increases are always the major factor.

Are peaceful or violent protests more effective?

Are peaceful or violent protests more effective at achieving policy change? I study the effect of protests during the Civil Rights Era on legislator votes in the US House. Using a fixed-effects specification, my identifying variation is changes within the congressional district over time. I find that peaceful protests made legislators vote more liberally, consistent with the goals of the Civil Rights Movement. By contrast, violent protests backfired and made legislators vote more conservatively. The effect of peaceful protests was limited to civil rights-related votes. The effect of violent protests extended to welfare-related votes. I explore alternative explanations for these results and show that the results are robust to them. Congressional districts where incumbents were replaced responded more strongly. Furthermore, congressional districts with a larger population share of whites responded more strongly. This is consistent with a signaling model of protests where protests transmitted new information to white voters but not to black voters.

That is the abstract of the job market paper of Gábor Nyéki from Duke.