Plausibility Index

Not all theories are created equal.

Some are backed by decades of rigorous research, replicated across cultures and contexts. Others are elegant ideas that captured the popular imagination but crumble under scrutiny. Most fall somewhere in between.

The Plausibility Index is Theorypedia's proprietary rating system designed to give you an honest, at-a-glance signal of how well-supported a theory actually is. It's not a judgment of whether a theory is interesting or useful — it's an assessment of how much credible evidence stands behind it.

How we score

Every theory is evaluated on five criteria, each scored from 1 (minimal support) to 5 (exceptional):

Empirical Evidence (30%) — Has this theory been tested through controlled studies, experiments, or systematic observation? How strong is the data?

Replicability (20%) — When other researchers have attempted to reproduce the original findings, do they get the same results? Has it survived the replication crisis?

Expert Consensus (20%) — What do specialists in the relevant field actually think about this theory? Is it widely accepted, actively debated, or largely dismissed?

Predictive Power (15%) — Does this theory successfully predict outcomes in new situations? Can it tell us what will happen, not just explain what already did?

Practical Utility (15%) — Does this theory work in practice? Can individuals, organizations, or policymakers apply it to make better decisions?

The verdict scale

The overall score is a weighted average of all five criteria, rounded to one decimal place. Each score maps to a plain-language verdict:

4.5–5.0 — Rock Solid. Among the most well-supported ideas in its field. You can build on this with confidence.

3.5–4.4 — Strong Foundation. Well-supported with minor gaps or ongoing refinements. The core holds up.

2.5–3.4 — Promising but Debated. Meaningful evidence exists, but so do significant questions. Worth understanding, but hold loosely.

1.5–2.4 — Intriguing but Shaky. More questions than answers. The idea is compelling, but the evidence isn't there yet.

1.0–1.4 — Mostly Myth. Little credible support despite popular appeal. Fascinating as a cultural phenomenon, unreliable as a guide to reality.

Our editorial commitment

Popularity does not equal plausibility. A theory can be culturally important, widely cited, and personally meaningful while still scoring a 2. We think intellectual honesty serves you better than false confidence, and the Plausibility Index is our way of delivering that honesty with every entry.