# Why isn’t “It worked really well for my brother-in-law” enough? 🧬

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- Last updated: 2026-08-15
- Page title: Why isn’t “It worked really well for my brother-in-law” enough? 🧬 | Assoc. Prof. Dr. Alişan Burak Yaşar

> The 5 Layers of Scientific Knowledge: Why isn’t “It worked really well for my brother-in-law” enough? 🧬 A treatment that helped someone you know is not pr

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# Why isn’t “It worked really well for my brother-in-law” enough? 🧬

April 27, 2026Recent Articles

The 5 Layers of Scientific Knowledge:
Why isn’t “It worked really well for my brother-in-law” enough? 🧬

A treatment that helped someone you know is not proof that it will help you too. Science assesses how reliable information is across 5 different layers 👇

🔴 Layer 1 — Case Reports: “This happened to one person.” Just a signal, not proof.

🔴 Layer 2 — Observational Studies: “This was observed in people who did that.” They show an association, but do not establish cause and effect.

🔵 Layer 3 — Randomized Controlled Trial (RCT): The gold standard that rules out chance and hidden confounders. It has three principles: randomization, a control group, and double-blinding.

🔵 Layer 4 — Meta-analysis & Systematic Review: Bringing dozens of studies together. At the top of the evidence hierarchy: Level I.

🟡 Layer 5 — Clinical Guidelines: The final stage, where science says, “This is what doctors should do.” They are transparent: they clearly label the level of evidence for each recommendation.

⚠️ Important: Helping someone you know is not enough on its own. A celebrity praising it on television does not mean it will benefit you too.

✅ Remember:
A treatment “helping someone” is a POSSIBILITY.
Its efficacy, established through scientific methodology, is a REALITY.

In healthcare, methodology saves lives—not miracles.

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