6 ms·

While it's certainly more robust, it still has some issues. For example, I remember reading that because the initial results for the experiment measuring the si

While it's certainly more robust, it still has some issues. For example, I remember reading that because the initial results for the experiment measuring the size of the electron was too low, every experiment afterwards reported slightly bigger sizes until they reached the correct value. Since they trusted the original result, if their results varied too much they discarded them. Ultimately they redid the experiment until they got something closer, and the only values that ended up getting published were results that were slightly bigger. Correct me if I am wrong, as I read this story a while ago.

knzhou 7y ago
That's an old Feynman story, but he was kind of bullshitting to make a point. If you actually look at the history of measurements, it doesn't look like that at all -- it instantly corrects to about the correct value right after Milliken and hovers around that value. https://hsm.stackexchange.com/questions/264/timeline-of-measurements-of-the-electrons-charge https://hsm.stackexchange.com/questions/264/timeline-of-meas...
- vadansky 7y ago
  Actually if you look at the follow up answer, they added some more measurements that back up Faynman's claim.
  - knzhou 7y ago
    Huh, I didn’t even know! The new answer really does change things.
- SiempreViernes 7y ago
  There is similar example for the speed of light as well.
astro123 7y ago
This is exactly the sort of thing that blinding is there to prevent. It is the same reason we in cosmology blind our data - to prevent us from biasing ourselves towards what other experiments have found. Also, the charge of the electron experiments you are talking about happening over 100 years ago, so not that relevant to today :)
jsweojtj 7y ago
I think you're thinking of the oil-drop experiment for the charge of the electron that was done 110 years ago (1909). And the experiments in the subsequent decades. Feynman, in 1974, so 45 years ago, used it as an example of problems in science. So, in response to the original post saying that particle physics has been doing things more or less correctly for decades is not tarnished by your example. More details here: https://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan's_experiment_as_an_example_of_psychological_effects_in_scientific_methodology https://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan's...
johnminter 7y ago
This is where measurements by multiple groups come in. I would point out that in 2019 the basis for the SI base units were changed because of issues with the standards. The international community - lead primarialy by NIST and their counterpart agencies in other countries noted that, among other standards, that measurements of the "standard meter" bars were changing measureably and the replicates of the "official bars" differed from one another. They proposed and agreed upon new "standards" based upon measurments with better precision and accuracy. See the Wikipedia summary [1] [1] https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_ba...
im3w1l 7y ago
Seems like a bias-variance tradeoff. It's not obvious to me that what they did was bad.

knzhou 7y ago

That's an old Feynman story, but he was kind of bullshitting to make a point. If you actually look at the history of measurements, it doesn't look like that at all -- it instantly corrects to about the correct value right after Milliken and hovers around that value. https://hsm.stackexchange.com/questions/264/timeline-of-measurements-of-the-electrons-charge https://hsm.stackexchange.com/questions/264/timeline-of-meas...

vadansky 7y ago
Actually if you look at the follow up answer, they added some more measurements that back up Faynman's claim.
- knzhou 7y ago
  Huh, I didn’t even know! The new answer really does change things.
SiempreViernes 7y ago
There is similar example for the speed of light as well.

astro123 7y ago

This is exactly the sort of thing that blinding is there to prevent. It is the same reason we in cosmology blind our data - to prevent us from biasing ourselves towards what other experiments have found. Also, the charge of the electron experiments you are talking about happening over 100 years ago, so not that relevant to today :)

jsweojtj 7y ago

I think you're thinking of the oil-drop experiment for the charge of the electron that was done 110 years ago (1909). And the experiments in the subsequent decades. Feynman, in 1974, so 45 years ago, used it as an example of problems in science. So, in response to the original post saying that particle physics has been doing things more or less correctly for decades is not tarnished by your example. More details here: https://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan's_experiment_as_an_example_of_psychological_effects_in_scientific_methodology https://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan's...

johnminter 7y ago

This is where measurements by multiple groups come in. I would point out that in 2019 the basis for the SI base units were changed because of issues with the standards. The international community - lead primarialy by NIST and their counterpart agencies in other countries noted that, among other standards, that measurements of the "standard meter" bars were changing measureably and the replicates of the "official bars" differed from one another. They proposed and agreed upon new "standards" based upon measurments with better precision and accuracy. See the Wikipedia summary [1] [1] https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_ba...

im3w1l 7y ago

Seems like a bias-variance tradeoff. It's not obvious to me that what they did was bad.