Experiment to test for causality

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Discussion Overview

The discussion centers around the design of an experiment to test the effectiveness of a specially treated bitter gourd product, marketed as BitterHeal, in lowering blood sugar levels in diabetics. Participants explore the implications of having three groups in the study, including a control group, and the potential influence of the placebo effect on the results.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question the necessity of having three groups (A, B, C) instead of just two (treatment and control), suggesting that the third group may not be essential for controlling the placebo effect.
  • Others argue that group C is important to rule out any beneficial effects of untreated bitter gourd, whether real or imagined.
  • Participants discuss various possible outcomes of the experiment and their implications for determining the effectiveness of BitterHeal.
  • There is a suggestion that if group B (untreated bitter gourd) shows no difference compared to group C (no treatment), it could indicate that untreated bitter gourd has no antidiabetic effect.
  • Some participants express uncertainty about how to distinguish between the effects of untreated bitter gourd and the placebo effect if group B shows a significant difference from group C.
  • Concerns are raised about the blinding of the study, with discussions on the importance of ensuring that neither participants nor researchers know which group receives which treatment to reduce bias.

Areas of Agreement / Disagreement

Participants generally agree on the importance of controlling for the placebo effect and the need for a control group, but there is no consensus on the necessity of having three groups versus two. The discussion remains unresolved regarding the implications of the different outcomes and the effectiveness of the experimental design.

Contextual Notes

Participants express concerns about the potential for bias in the study design and the challenges of achieving a fully blinded experiment. There are also discussions about the assumptions underlying the interpretation of the results.

  • #31
AFAIK the placebo effect does not occur in studies involving physical changes in body chemistry like serum cholesterol, and blood sugar. It is significant in studies of the subjective effect of a medication as in pain relief or mood change.

When comparing two medications for effectiveness you compare it to a (gold)standard commonly used for the treatment. The problem as I see it with this study is that we are comparing two medications of marginal value.

I assume this problem was from a statistics course, but did they fully realize the issues with this scenario? The question is what was the intent of the problem? What did they want you to learn from it?

I think you need group C to establish the effectiveness of B as well as the effectiveness of A in lowering blood sugar. Next, you can compare A and B to determine their relative effectiveness.
 

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