How this works

The size of each disease is measured in healthy years lost, known in public health as DALYs (disability-adjusted life years). One DALY is one year of healthy life lost. The figures come from the Global Burden of Disease study (2023), which estimates them for the whole world each year.

They add up two kinds of loss:

1. Years lost to dying early. For each death, the years that person would normally have gone on to live. A child who dies at 5 loses more than 80 years; a person who dies at 80 loses far fewer. The same reference life expectancy is used everywhere, so a death at a given age counts the same in every country.
2. Years lived in poor health. Each condition has a severity weight between 0 (full health) and 1 (as bad as death), set from large surveys that ask people to compare health states. A year with severe depression counts as a large share of a year lost; a year with mild back pain counts as a small share. Small shares add up: back pain ranks high because hundreds of millions of people have it.

Healthy years lost = years lost to dying early + years lived in poor health.

This puts diseases that kill, like heart disease or malaria, on the same scale as diseases that disable without killing, like depression or hearing loss. Ranking by deaths alone would leave the second group out.

These are modeled estimates, not head counts, because many countries lack complete records. Each disease page shows the 95% uncertainty range alongside the estimate.

We measure attention two ways, both as rough proxies:

• Active clinical trials on ClinicalTrials.gov: recruiting, about to recruit, or running.
• Papers published in 2025 on PubMed, using the standard medical subject heading for the disease where one exists.

To compare diseases of different sizes, we divide by the size of the problem: active trials per million healthy years lost. Think of it like doctors per thousand people. A disease with many trials for its size is well served; one with few is stretched thin.

Heart disease is the bigger problem, but it has about 6 times more trials for its size. Lower means more neglected.

A low number doesn't always mean more research is the answer. Measles already has a cheap, effective vaccine; most of its harm comes from people not getting it. Neglect can be a research gap or a delivery gap.

Each disease gets three scores from 0 to 1, based on where it ranks among the 142 diseases with a burden estimate (a percentile, so one extreme value can't swamp the rest):

Impact

Healthy years lost per year.

Neglect

The average of two ranks: healthy years lost per active trial, and per paper published. Fewer trials and papers for the size of the problem scores higher.

Readiness

The average of two ranks from Open Targets: gene targets with strong evidence, and drugs or clinical candidates already studied. It measures how much known biology there is to build on. Diseases missing from Open Targets are scored on impact and neglect only, so they aren't penalized.

Your slider settings weight the three, and the leaderboard ranks by the weighted average. The presets are:

• Balanced · impact 50, neglect 50, readiness 25
• Biggest burden · impact 100, neglect 0, readiness 0
• Most neglected · impact 30, neglect 100, readiness 0
• Most to build on · impact 40, neglect 40, readiness 100

Each disease page shows how far the field has come, on a five-step ladder derived from Open Targets drug and target data. Nothing here is self-reported.

1. 01Early understanding: No strong gene target or drug candidate yet.
2. 02Target found: At least one gene target with strong evidence.
3. 03Drug candidates: Preclinical or phase 1 drug candidates.
4. 04In trials: Drug candidates in phase 2 or later.
5. 05Has approved drugs: At least one approved drug; not necessarily a cure.

"Has approved drugs" means at least one drug is approved for the disease, not that it is cured. Most common diseases reach this step, so the ladder separates rare and neglected diseases better than common ones.

• Global Burden of Disease 2023 ↗

  Healthy years lost, deaths and prevalence, global, all ages. Global Burden of Disease Collaborative Network. Global Burden of Disease Study 2023 (GBD 2023) Results. Seattle, United States: Institute for Health Metrics and Evaluation (IHME), 2024.

• ClinicalTrials.gov ↗

  Active and total clinical trials, searched by disease name, its medical subject heading and synonyms.

• PubMed ↗

  Papers published per year, from the U.S. National Library of Medicine.

• Open Targets Platform ↗

  Gene targets, drugs and clinical candidates, and disease identifiers. Released under CC0.

Data last updated November 12, 2026. Disease pages link to the source searches used for their counts.

• Trials and papers measure attention, not progress. A large trial and a small pilot each count once, and lab research, datasets and AI projects don't show up at all.
• Some burden figures don't match the disease exactly. GBD groups some conditions, so ALS is counted as all motor neuron disease, for example. Disease pages flag these.
• 76 diseases aren't ranked because GBD doesn't estimate them separately. Most are rare genetic diseases, which the burden data covers poorly.
• Labels differ between sources. GBD counts hypertensive heart disease separately, but most research on it is filed under hypertension, so its attention looks lower than it is.
• Search terms shape the counts. We search names, subject headings and synonyms, and record each exact query, but some trials and papers will still be missed or miscounted.

This site is for research planning. It is not medical advice.