World Suffering Index (WSI)

1. What is the World Suffering Index (WSI)?

WSI is a long‑term project to describe how much suffering people actually experience in different parts of the world, year by year.

It uses a new unit, the Universal Suffering Unit (USU), to quantify “how bad it feels to live through something” on a scale anchored to familiar experiences.

In early editions, WSI will report USU totals and deaths by country, region, and major cause. In later versions, we plan to add a simple “years of life lost” companion metric, but the current focus is on experienced suffering (USU) + deaths.

WSI is meant to be complementary to existing metrics like DALYs, QALYs, HDI, or the Global Peace Index, not a replacement.

2. How could WSI be used in practice?

WSI could help:

• Global health & humanitarian planning – compare the suffering burden (USU) of different crises and diseases across regions, to prioritise where extra resources are likely to reduce the most suffering, not just the most cases.
• Philanthropic decisions – give donors a common yardstick (USU + deaths) to compare very different interventions (e.g., malaria prevention vs mental‑health vs disaster response).
• Policy analysis – evaluate how proposed policies might change suffering (e.g., “what USU reduction do we expect from scaling up chronic‑pain treatment vs expanding disaster‑resilience infrastructure?”).
• Tracking progress over time – see whether a country’s experienced suffering is actually falling, staying flat, or shifting from one cause to another, rather than relying only on GDP or life expectancy.
• Communication and advocacy – translate complex burdens (like displacement plus disease plus fear) into a single, anchored, explainable unit (“this year’s floods were roughly equivalent to X million kidney‑stone episodes of suffering”). WSI is not meant to dictate decisions, but to give governments, NGOs, and funders a clearer shared picture of where and how people are suffering.

3. What is a Universal Suffering Unit (USU)?

USU is a calibrated measure of experienced suffering that scales with:

• Intensity (how bad it feels at a moment);
• Duration (how long it lasts); and
• Number of people affected.

Formally, USU aggregates intensity‑over‑time curves, with a small convexity (p ≥ 1) so that very intense states count more than mild ones lasting the same time.

To keep the scale intuitive, USU is anchored to common experiences:

• Roughly 0.001 USU – a brief needle stick for a blood draw.
• Roughly 0.01 USU – a paper cut or stubbed toe.
• Roughly 0.1 USU – a second‑degree burn on a fingertip with a few hours of throbbing.
• 1.0 USU (by definition) – a “typical” episode of renal colic (kidney‑stone pain) over its full trajectory.

So if a country‑year has “80 million USU”, you can loosely read that as: “The total suffering experienced was about as bad as 80 million full kidney‑stone episodes, or 800 million fingertip burns, or 80 billion needle sticks.”

The exact comparisons are approximate, but the point is to keep the unit psychologically grounded.

4. Why use kidney‑stone pain as the 1.0 USU anchor?

Renal colic (kidney‑stone pain) is:

• Very intense for most people;
• Well‑studied in clinical pain literature; and
• Common enough that many clinicians and some patients have direct experience with it.

We model a typical renal‑colic episode as an intensity‑over‑time curve using published pain scores (e.g., initial spike, sustained severe phase, relief after treatment). We then choose a calibration constant so that this full trajectory equals 1.0 USU.

That anchor gives other experiences something to compare to, for example:

• “A day in this shelter feels like 10–20% of a kidney‑stone episode.”
• “This condition, over a month, is more like several kidney‑stone equivalents.”

Anchors can be updated over time if better candidates emerge; the key is that they are transparent and reversible, not a black box.

5. What does WSI measure, and what does it not measure?

WSI is focused on human suffering as experienced. It does not aim to measure:

• Economic output or productivity;
• “Social value” of people; or
• Moral worth, dignity, or rights.

Instead, it asks: “Across a population, how much bad experience happened this year?”

For now, WSI describes events in terms of:

• USU totals – suffered experience (e.g., illness, injury, displacement, fear, grief); and
• Deaths – how many people died.

Future versions may include a formal “years of life lost” companion metric, but that is deliberately separated from USU so we don’t collapse “how bad it feels” and “how long life is cut off” into one hidden mix.

6. How do you map a specific experience (e.g., a year of displacement, a week of hunger) onto the USU scale?

We use a structured recipe:

• Define the state clearly. Example: “Living in a crowded gymnasium shelter for 3 months, basic food and water, minimal privacy, no direct violence.”
• Place a typical day on the 0–10 intensity scale using the anchor ladder. Panels of people who know the context (including, where possible, people with lived experience) are asked: “On most days, is this closer to a paper cut, a fingertip burn, or a fraction of a kidney‑stone day?” That yields a band, e.g. 3–5 out of 10, not a single point.
• Specify duration and pattern. Is the intensity fairly constant, or are there acute spikes (e.g., initial days worse, some adaptation later)? For displacement, we might model: first 2–4 weeks at intensity 5–7, subsequent months at 3–5.
• Multiply by population. If 100,000 people are in that state for 90 days, we compute their individual USU trajectories and sum them.
• Represent uncertainty explicitly. We treat intensities and durations as distributions (e.g., 3–5 becomes a random variable), run Monte‑Carlo simulations, and report median USU with a 90% uncertainty interval.

This mapping is organised in a USU Catalogue – a versioned library of “typical intensity + duration” bands for common states (dengue, flood displacement, moderate depression, etc.), with context modifiers for severity. The catalogue is explicitly marked as provisional and will be refined as more experts weigh in.

7. How do you handle psychological suffering versus physical pain?

USU is designed for any experienced suffering, not just physical pain.

To incorporate psychological states (e.g., anxiety, depression, grief, terror):

• We map standard mental‑health scales (PHQ‑9, GAD‑7, PTSD scales, etc.) onto the same 0–10 intensity ladder, using both literature and structured expert judgement.
• We calibrate these mappings by asking comparative questions such as: “On most days, does moderate depression feel closer to a 0.01 anchor (paper cut) or to 0.1 (fingertip burn), if you scale up over the whole day?”
• We then specify expected durations (e.g., months for an untreated depressive episode) and integrate them into USU like any other intensity‑over‑time curve.

In the Catalogue, psychological states live alongside physical ones; the method is the same, but the data sources and experts differ.

8. How do you handle people who are suffering from several things at once?

We treat co‑occurring harms within the same person differently from harms across different people:

• Across different people, USU is simply additive.
• Within the same person and time window (e.g., same day), we don’t just add intensities.

The current rule of thumb:

• For each person‑day, we take the strongest state as the baseline.
• Additional states can add some extra intensity, but total intensity is capped at a plausible ceiling (e.g., “worse than kidney‑stone pain” is rare).
• The overlap rule is simple and transparent, so others can critique or change it and recompute.

This prevents double‑counting when someone is simultaneously sick, hungry, and displaced, while still acknowledging that being hit by multiple harms at once is worse than any one alone.

9. How does WSI relate to DALYs, QALYs, HDI, and other indices?

WSI is designed to sit alongside these, not to replace them:

DALYs / QALYs

• DALYs measure time lived with disability plus years of life lost; QALYs measure time lived at different quality levels.
• They are time‑based and health‑focused.
• USU focuses on experienced suffering itself and can be used for non‑health harms (e.g., displacement, violence, terror, grief) that are not neatly captured in DALYs.

HDI (Human Development Index)

• HDI tracks education, income, and life expectancy as “capabilities”.
• A country can have high HDI and still high suffering (e.g., mental‑health problems, conflict).
• WSI shows the suffering side; HDI shows the opportunities side.

Other indices (Misery Index, Global Peace Index, International Human Suffering Index, etc.)

• These are composites of indicators (inflation + unemployment, conflict scores, development measures).
• They typically do not use an experiential unit like USU; WSI attempts to put different harms on a shared experiential scale anchored to real sensations.

In many applications we expect USU/WSI to be used together with DALYs, QALYs, and HDI: each reveals different aspects of reality.

10. How subjective is this? Can the assumptions be challenged?

The framework is unavoidably value‑laden, just like DALY disability weights or any welfare measure. Instead of hiding that, WSI tries to:

• Make every step explicit (anchors, intensity bands, durations, overlap rules).
• Provide open templates and the full USU Catalogue used for each report.
• Use bands and uncertainty intervals, not single precise‑looking numbers.
• Encourage others to propose alternative anchors, tweak intensity mappings, and rerun the same calculations with different ethical assumptions.

The goal is not to fix the “one true” conversion of suffering into numbers, but to provide a transparent baseline that others can build on or critique.

11. Where do the data come from?

For early WSI reports, most inputs will come from:

• Global public‑health databases (e.g., WHO, Global Burden of Disease);
• Humanitarian and disaster datasets (e.g., UN agencies, major NGOs);
• Demographic data (UN, World Bank); and
• Peer‑reviewed studies on pain, mental health, displacement, and related fields.

The USU Catalogue will explicitly cite the sources used for each state (e.g., “dengue intensity based on specific studies”, “displacement bands based on UNHCR reports + expert elicitation”). Over time, WSI will incorporate direct survey data and better models where available.

12. How can other researchers use or critique WSI and USU?

Everything is designed to be reproducible and adjustable:

• The methods preprint is open access, with a DOI.
• Templates and example CSVs are publicly available as supplementary files.
• The emerging USU Catalogue will be versioned and documented.

Researchers can:

• Apply USU to their own datasets;
• Propose alternative anchors or exponent values;
• Re‑calibrate intensities for specific conditions; and
• Publish critiques, replications, or variations.

WSI welcomes this: the aim is not to “own” the one true scale, but to make it easier for many groups to think clearly about suffering in a comparable way.