Absolute versus relative risk: read the numbers behind a claim
A hypothetical worked example shows why a percentage reduction needs a baseline risk, a defined outcome and a time frame before it becomes useful.
Every review on this site carries one of three verdicts, and the verdict applies to the claim as stated — not to the general idea behind it.
- Supports — consistent findings from well-designed studies, with effect sizes large enough to matter.
- Mixed — real effects, but inconsistent across studies, small, or measured over too short a period to act on confidently.
- Insufficient — not enough evidence to support the claim, including cases where the available evidence points the other way.
A verdict of insufficient is not a statement that something does not work. It is a statement that the evidence does not currently justify the claim being made for it, which in a market built on confident claims is the more useful answer.
Current verdicts
insufficient
Routine whole-body MRI for people without symptoms or known elevated risk
Detection alone does not establish a net health benefit. Read the source-based review below.
mixed
Interpreting incidental findings
Findings need clinical context and follow-up; a scan result is not a treatment decision.
insufficient
Treating a normal scan as an all-clear
A screening result cannot answer every health question or predict future disease.
| Question | General screening | Diagnostic investigation |
|---|---|---|
| Why is it proposed? | Check for disease before symptoms | Investigate a defined concern |
| What should be explained? | Evidence of benefit, harms and follow-up | How the test could change care |
| Who decides suitability? | You and a qualified clinician | You and the treating team |
Latest reviews
A younger biological-age score: what would show a real health benefit?
A change in an aging marker is not, on its own, proof of extra healthy years. Separate the measurement, its intended use and the clinical outcome it is supposed to predict.
A worksheet for checking a longevity test's evidence
Record the claim, study population, comparison, outcomes and harms before deciding what the evidence does and does not establish.
Screening versus diagnostic testing
The purpose of a test changes the evidence it needs. Compare screening, investigation of symptoms and follow-up of an abnormal result before evaluating a claim.
Whole-body MRI for people with no symptoms: what the evidence shows
Whole-body MRI can detect abnormalities, but detection alone does not establish a health benefit. A source-based review of incidental findings, follow-up and uncertainty.
Does 'without diabetes' mean a trial studied healthy adults?
Read the rest of the eligibility criteria before applying a result to a different population. A cardiovascular trial provides a concrete example of why one absent condition does not define overall health.
For the limitations of the evidence reviewed, see the whole-body MRI article listed here. A detection rate is not a survival benefit, and a normal scan is not a promise about future health.