3 ms·

Worthless without control group

by loopz 6y ago

AstralStorm 6y ago
Technically people who did not take the drug are a control group. It's just not placebo controlled. (Which is quite a big no. Unless there's a known working treatment, which should be used as the control then.) The big question is, how well randomized are these, and what's the effect size - could be suspiciously small. If it's not randomized at all, the results do not necessarily show the drug is good - just that it's given to healthier patients. You can try to reduce such artifact by considering matching reference subgroups.
- gus_massa 6y ago
  Did they have the same inclusion criteria? The people in the treatment group probably have to sign a conformity form, this implicitly exclude people that is too wasted to even hold a pen and that probably have a worse prognosis than the average. Did they include people with more than 90 years old? People with a recent previous heart attack? Small children (parents are annoying)? Without the same inclusion criteria it's not a control group but a unrelated bunch of guys.
  - AstralStorm 6y ago
    Also known as randomized control group. That said, it should be equivalent to treatment group. Which is exactly what I said. That's the reason why in RCTs treatment and control groups are split from the same pool - less need to make sure they are.
    - gus_massa 6y ago
      I think we agree. Just remember that the first study by Raoult claims to have a control group, but it's better described a a unrelated bunch of guys in another city. And there are other studies with similar tricks.
- loopz 6y ago
  They're all wildly different populations within different environments and infection rates. COVID-19 infects with very stochastic clustering, making controlled experiments difficult. So one may even need global meta-studies with local control groups, for meaningful results. During an uncontrolled pandemic, you just don't have that luxury and enough degree of control.
zaroth 6y ago
What do you mean? The 2,451 patients are partly made up of control group, namely, those who didn’t get the experimental treatment.

Worthless without control group

by loopz 6y ago

Worthless without control group

Technically people who did not take the drug are a control group. It's just not placebo controlled. (Which is quite a big no. Unless there's a known working treatment, which should be used as the control then.) The big question is, how well randomized are these, and what's the effect size - could be suspiciously small. If it's not randomized at all, the results do not necessarily show the drug is good - just that it's given to healthier patients. You can try to reduce such artifact by considering matching reference subgroups.

gus_massa 6y ago
Did they have the same inclusion criteria? The people in the treatment group probably have to sign a conformity form, this implicitly exclude people that is too wasted to even hold a pen and that probably have a worse prognosis than the average. Did they include people with more than 90 years old? People with a recent previous heart attack? Small children (parents are annoying)? Without the same inclusion criteria it's not a control group but a unrelated bunch of guys.
- AstralStorm 6y ago
  Also known as randomized control group. That said, it should be equivalent to treatment group. Which is exactly what I said. That's the reason why in RCTs treatment and control groups are split from the same pool - less need to make sure they are.
  - gus_massa 6y ago
    I think we agree. Just remember that the first study by Raoult claims to have a control group, but it's better described a a unrelated bunch of guys in another city. And there are other studies with similar tricks.
loopz 6y ago
They're all wildly different populations within different environments and infection rates. COVID-19 infects with very stochastic clustering, making controlled experiments difficult. So one may even need global meta-studies with local control groups, for meaningful results. During an uncontrolled pandemic, you just don't have that luxury and enough degree of control.

zaroth 6y ago

What do you mean? The 2,451 patients are partly made up of control group, namely, those who didn’t get the experimental treatment.