>_ Why This Matters: The psychology of numbers
Genetic results are particularly vulnerable to dramatic framing.
Imagine reading: “Your genotype is associated with a 70% increase in risk.” Most people naturally focus on the 70%.
But what was the baseline risk? Over what period? In what population? At what age? Was the study measuring actual risk—or odds?
Without those answers, the percentage alone cannot describe your personal probability.
Research on risk communication repeatedly shows that relative measures make effects appear larger than presentations based on absolute risk.
>_ Where Genetics May Contribute: Odds Ratios vs Relative Risk
Many genetic association studies report an Odds Ratio (OR), often per allele (e.g., OR = 1.20).
That does not automatically mean your probability of the condition increases by 20%. An odds ratio compares odds rather than probabilities.
When an outcome is rare, an odds ratio may approximate relative risk reasonably well. As outcomes become more common, the two measures diverge substantially.
An interpretation engine should preserve original statistical measures instead of silently converting OR 1.20 into “20% higher personal risk.”
>_ What Is Absolute Risk?
Absolute risk answers: What is the probability that this event occurs over a specified period?
That timeframe is crucial. Five-year risk, ten-year risk, and lifetime risk are completely different quantities. Age, sex, family history, and clinical biomarkers all contribute. A genotype modifies one component of a risk model without determining the entire result.
>_ A Simple Example
100 out of 10,000 develop outcome
Absolute Risk: 1.0%150 out of 10,000 develop outcome
Absolute Risk: 1.5%• Relative Risk: 1.5 (50% higher relative risk)
• Absolute Difference: 0.5 percentage points (50 additional cases per 10,000 people)
Every description above is mathematically compatible. But “50% higher risk” alone gives the least context.