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The Randomness of Science - Why Randomised Controlled Trials (RCTs) Work - FutureIQ

4,109 views • Feb 28, 2025
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Concepts in this episode

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  1. Post Hoc Ergo Propter Hoc mental-model

    Sequential stories feel causal because the mind turns “after this” into “because of this.” The real test is whether the intervention made recovery more likely than it would have been without the intervention.

  2. Controlled Trial mechanism

    A controlled trial tests an intervention by comparing outcomes in otherwise comparable groups that differ in whether they receive it. The gap between their outcomes is the causal signal.

  3. Randomization mechanism

    Random assignment spreads hidden individual differences across groups. With enough participants, those differences roughly cancel out, leaving the treatment as the clearest systematic distinction.

  4. Randomized Controlled Trial principle

    A randomized controlled trial isolates causation by creating comparable groups and making the suspected intervention their clearest systematic difference. If outcomes do not diverge, the intervention is unlikely to be the cause.

  5. Placebo effect mechanism

    Expectation can produce genuine perceived relief even when a remedy has no active ingredient. Feeling better therefore does not prove the treatment worked; the test is whether it performs better than belief and natural recovery.

  6. Selection Bias mechanism

    Selection bias occurs when the path into a sample systematically excludes cases, making patterns produced by that filter look like properties of the wider world. Before trusting a relationship, reconstruct how each observed case became visible.

  7. Nocebo Effect mechanism

    Negative expectations can become part of an outcome: warning people that something will make them worse may help produce the worsening they expect. Experiments must therefore separate a treatment’s effects from the effects of belief and emotional framing.

  8. Confounders mental-model

    A confounder is a difference between groups that can impersonate the effect of a treatment. Keeping conditions comparable—and using random assignment when hidden differences cannot be measured—makes the treatment the clearest remaining explanation.

Description

Do you know what a Randomised Controlled Trial (RCT) is? How and why are such trials conducted? Today, the 28th of Feb is World Science Day and hence in true FutureIQ style, it seemed fitting to talk about one of the pillars of good science - RCTs. In this episode, we speak about the need for RCTs and how they came about to be. What are the different groups/phases within Randomized Controlled Trials? How does the Placebo effect play a role within RCTs? Along with giving several examples, we also explain the different variables and baises that are addressed through RCTs such as Observer Bias, Confounders Bias and Selection Bias. While RCTs are a pretty common and standardised practice within epidemiology, there are natural questions that arise about the ethics of the practice as well. How fair is it to the participants of the trial? And where does the line of morality lie in finding the balance for the greater good of the world? More videos you may enjoy: Barnum Effect Explained: https://youtu.be/FcSuHP113NI Survivorship Bias Explained: https://youtu.be/QjDXyuBJ0UY Hope you enjoyed FutureIQ by Navin Kabra and Shrikant Joshi. Do hit us up on Twitter: @ngkabra http://twitter.com/ngkabra @shrikant https://twitter.com/shrikant Listen it on the podcast provider of your choice: https://tapthe.link/FutureIQRSS Chapters: 00:00 Introduction 01:45 Why do we need RCTs? 03:55 Ad Hoc Fallacy 04:54 Scurvy and the start of Controlled Trials 07:44 Placebo Effect 10:30 So how do we find the balance? 13:29 3 Major biases solved by RCTs 15:03 Selection Bias 17:25 Confounder's Bias 19:10 Observer Bias 21:40 Double Blind 22:33 Ethics of RCTs External sources that are cited: - Lobotomy: https://en.wikipedia.org/wiki/Lobotomy - Bloodletting: https://en.wikipedia.org/wiki/Bloodletting - Data analysis shows that religious authorities develop systems of “praying for rainfall” which maximizes the chances of prayer happening just before rainfall: https://www.nber.org/papers/w31411 - The Illinois Employee Wellness Program https://www.nytimes.com/2018/08/06/upshot/employer-wellness-programs-randomized-trials.html - Coffee and Lung-cancer (correlated, but really it is because coffee drinkers are also smokers): https://pubmed.ncbi.nlm.nih.gov/19362749/ - Lack of pirates is causing global warming: https://www.forbes.com/sites/erikaandersen/2012/03/23/true-fact-the-lack-of-pirates-is-causing-global-warming/?sh=5ac145893a67 - Website of spurious correlations: https://www.tylervigen.com/spurious-correlations - Clever Hans, the horse who could do maths: https://www.youtube.com/watch?v=hAJlAuEo7Ac - Parachute RCT: https://www.bmj.com/content/363/bmj.k5094 #futureiq

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