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raphlinus's profile
Raph Levien
Raph Levien
Raph Levien
@raphlinus

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Raph Levien

@raphlinus

Rust. Fonts. Graphics. Quaker. Independent. he/him

Berkeley, CA
levien.com
Joined May 2009

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    1. Cheryl Rofer‏ @CherylRofer Apr 12
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      Rant on modeling 1. There are a hundred gazillion models out there. Few of their owners have bothered to compare their model to others to see what is working and what isn't.

      23 replies 144 retweets 406 likes
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    2. Cheryl Rofer‏ @CherylRofer Apr 12
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      2. By the standards of the models I've worked with, they are all simple - a few differential equations, a curve fit. I've worked with a hundred or more elementary reactions and then a mass- and heat-transfer model that incorporated those in. (Hint: we had to boil them down to six

      3 replies 8 retweets 74 likes
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    3. Cheryl Rofer‏ @CherylRofer Apr 12
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      3. The only model I have seen that is at all transparent about its parameters is the Imperial College model. All the others I have seen are curve fits. They mumble about social distancing as a variable, but never say which parameter it fits into.

      2 replies 29 retweets 137 likes
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    4. Cheryl Rofer‏ @CherylRofer Apr 12
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      4. All the curve fits are with different functions. At least, back in the day when chemical kinetics was curve fitting, we always used the same function.

      1 reply 11 retweets 75 likes
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    5. Cheryl Rofer‏ @CherylRofer Apr 12
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      5. It looks like amateur hour. Everyone's got their pet model, but they're not telling us what it is. And a further layer of amateurs on Twitter say solemn words like "assumptions" that they have nothing to back up.

      2 replies 15 retweets 103 likes
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    6. Cheryl Rofer‏ @CherylRofer Apr 12
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      6. I've spent a lot of time on the Imperial College and IHME models. I don't intend to do that for every single model out there. https://nucleardiner.wordpress.com/2020/03/21/the-imperial-college-modeling-of-the-coronavirus/ …https://nucleardiner.wordpress.com/2020/04/07/the-ihme-epidemiological-model/ …

      3 replies 33 retweets 134 likes
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    7. Cheryl Rofer‏ @CherylRofer Apr 12
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      7. My assumption from here on in is that any model but the Imperial College model is crap until it's explained. With explicit connection of assumptions to parameters. And mansplaining this thread will get you blocked.

      16 replies 26 retweets 258 likes
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    8. Cheryl Rofer‏ @CherylRofer Apr 12
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      Tyler Cowen (and probably other economists who think they've got something to say) has never looked closely at the epidemiological models, judging from this. His questions are obnoxious. Ignore stuff like this.https://marginalrevolution.com/marginalrevolution/2020/04/what-does-this-economist-think-of-epidemiology.html …

      8 replies 20 retweets 124 likes
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      Raph Levien‏ @raphlinus Apr 12
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      Replying to @CherylRofer

      What do you think of the modeling work done by Eva K Lee, which has now come to light in the "Red Dawn" emails? Not exactly a great example of transparency, but from my non-expert evaluation, better than much of the work.

      11:04 AM - 12 Apr 2020
      1 reply 0 retweets 0 likes
        1. New conversation
        2. Cheryl Rofer‏ @CherylRofer Apr 12
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          Replying to @raphlinus

          I have not seen that yet.

          1 reply 0 retweets 0 likes
        3. Raph Levien‏ @raphlinus Apr 12
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          Replying to @CherylRofer

          https://int.nyt.com/data/documenthelper/6879-2020-covid-19-red-dawn-rising/66f590d5cd41e11bea0f/optimized/full.pdf … for the raw document, though the NYT has good interpretation of it in their coverage. Fascinating reading.

          0 replies 0 retweets 1 like
        4. End of conversation

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