The value of lasting relief
A brief illness can be intensely unpleasant. Persistent distress can also accumulate a substantial burden, even when its average intensity is lower. Counting people helped alone misses this difference.
USU brings intensity and duration into the same calculation. Under the current linear model, doubling either the average reduction in suffering or the time it lasts doubles the estimated relief, with other inputs held fixed.
One person, two hypothetical examples
A brief illness avoided
6.1 USU averted
4 days × 3 intensity points
Modest relief sustained
22.9 USU relieved
90 days × a 0.5-point reduction
See the arithmetic
USU = days × 24 × average intensity change ÷ 47.25.
Brief illness: 4 × 24 × 3 ÷ 47.25 ≈ 6.1 USU.
Lasting relief: 90 × 24 × 0.5 ÷ 47.25 ≈ 22.9 USU.
The denominator is the defined kidney-stone pain reference. The intensity changes are hypothetical assumptions, not clinical ratings converted into USU.
Duration makes the second estimate larger despite its smaller assumed intensity change. In a real intervention, the crucial question is whether that relief occurs, how long it lasts, and how much would have happened without the intervention.
How this appears in the four analyses
Each report makes a different part of suffering visible. Its population and credited time window determine what the number means.
| Analysis | What the model counts | What to look for |
|---|---|---|
| Malaria prevention | Young children’s acute illnesses avoided during three years of net protection. Each illness course is modeled in days. | Protection lasts longer than each illness it prevents. The estimate adds up avoided episodes. |
| Fistula repair | Assumed physical and emotional relief during postoperative days 91–365. | Persistent relief can accumulate. The result depends on how many women benefit and how long improvement lasts. |
| Depression relief | 90 assumed days of psychological relief within the first six months. | A screening result does not measure a USU reduction. The link to experienced relief is an explicit, uncertain assumption. |
| Eye-pain relief | Later physical pain relief during days 91–365, less an allowance for treatment pain. | Treatment can cause suffering as well as relieve it. This model subtracts one selected burden, not every possible harm. |
Deaths prevented and suffering relieved answer different questions
The malaria analysis estimates both avoided illness and deaths prevented. The other three leave deaths prevented unestimated. That means unknown, not zero.
USU describes experienced suffering, including illness before death where modeled. Death itself and lost years of life are separate outcomes. A small USU figure does not mean preventing a death has little value.
Keeping both outcomes visible lets us consider sustained relief alongside prevention without treating either number as a complete measure of human benefit.
What this means when considering where help could matter
The practical lesson is to ask what changes in someone’s experience, for how long, and at what cost. Before using a headline estimate, check:
- What does the spending buy? A donation estimate and a program-cost estimate start from different financial assumptions.
- What is included? Compare populations, benefit periods and treatment harms. The eye-pain model deducts selected recovery pain; the other three headlines report gross benefits.
- How secure are the assumptions? Costs, additional delivery, intensity and duration can all change the result. Look at the scenarios and the underlying evidence.
Our four headline figures do not establish which intervention is best. They provide a starting point for investigating both severe short-term suffering and persistent distress that might otherwise be overlooked.
About this synthesis
Based on WSI’s AMF malaria-prevention, fistula-repair, Friendship Bench and trichiasis-surgery reports, each model v0.1. Links in the table lead to their evidence, assumptions and reproducible calculations. This feature adds no new clinical finding, funding-status claim or change to those models.