Discussion Lead: Julian Jamison (University of Exeter)
Julian will frame the DALY-WELLBY conversion question and facilitate discussion.
Focal Question (DALY_01)
If the impact of one program is measured in WELLBYs and another program impact is measured in DALYs, and we have a reported effect size and standard deviation for each, what is the best numerical conversion or mapping between them?
Note: This may be treated as a secondary topic depending on time constraints.
Overview
This segment addresses the practical challenge of comparing interventions measured in different units. When funders want to compare StrongMinds[1]StrongMinds: group-based interpersonal therapy for depression in sub-Saharan Africa. Cost-effectiveness estimates range from highly cost-effective to uncertain depending on WELLBY valuation method. (measured in WELLBYs) to malaria bednets[2]Malaria bednets are GiveWell's top-recommended intervention, with well-established DALY impact estimates. They serve as a common benchmark for comparing other interventions. (measured in DALYs), what conversion factor should they use?
Current Approaches
| Approach | Description | Limitations |
|---|---|---|
| SD-equivalence[3]Standard deviation equivalence: treating 1 SD in WELLBY as equivalent to 1 SD in DALY. Simple but assumes distributions have comparable meaning, which may not hold. | 1 SD WELLBY ≈ 1 SD DALY | Assumes comparable distributions |
| Direct estimates | Literature-based conversion factors[4]Estimates vary widely: Frijters et al. suggest ~6 WELLBYs per DALY averted; some funders use higher values. Context and methodology drive differences. | Wide range (2-15 WELLBYs per DALY) |
| Stated preference[5]Directly asking people: "Would you trade X improvement in life satisfaction for Y years of life?" Vulnerable to framing effects—how questions are posed affects answers. | Survey-based trade-off elicitation | Framing effects, hypothetical bias |
Discussion Topics
- What conversion approach minimizes expected welfare loss?
- Should the conversion factor vary by intervention domain?
- How much precision is lost using rough approaches?
- What data would most reduce uncertainty?
Relevant Pivotal Questions
This discussion directly addresses several of our Pivotal Questions:
- DALY_01: What is the best numerical conversion or mapping between WELLBYs and DALYs?
- DALY_02: Should the conversion factor vary by intervention domain?
- DALY_03: How much does the conversion factor matter for real funding decisions?
- DALY_05: What empirical data would most reduce WELLBY-DALY uncertainty?
Key Literature
- Cooper (2023): "New approaches to measuring welfare"[6]Cooper's review in Fiscal Studies surveys methods for measuring welfare beyond GDP, including subjective wellbeing and capability approaches. Essential background for understanding WELLBY's theoretical foundations. (Fiscal Studies)
- "The WELLBY: a new measure of social value and progress"[7]This Nature article by Frijters et al. presents the WELLBY framework and its application to policy evaluation. Key reference for understanding how WELLBYs are intended to be used. (Nature, 2024)
Note: The "2-15 WELLBYs per DALY" range cited in the table requires verification; sources vary.
📄 Background: DALY↔WELLBY Conversion
This document maps the key conversion approaches: UK Green Book (~7:1), empirical estimates (5-10 WELLBYs per QALY), and the conceptual issues underlying different methods.
View Analysis →AI-assisted draft (Mar 2026) — annotate errors directly.
Notes
- StrongMinds: group-based interpersonal therapy for depression in sub-Saharan Africa. Cost-effectiveness estimates range from highly cost-effective to uncertain depending on WELLBY valuation method.
- Malaria bednets are GiveWell's top-recommended intervention, with well-established DALY impact estimates. They serve as a common benchmark for comparing other interventions.
- Standard deviation equivalence: treating 1 SD in WELLBY as equivalent to 1 SD in DALY. Simple but assumes distributions have comparable meaning, which may not hold.
- Estimates vary widely: Frijters et al. suggest ~6 WELLBYs per DALY averted; some funders use higher values. Context and methodology drive differences.
- Directly asking people: "Would you trade X improvement in life satisfaction for Y years of life?" Vulnerable to framing effects—how questions are posed affects answers.
- Cooper's review in Fiscal Studies surveys methods for measuring welfare beyond GDP, including subjective wellbeing and capability approaches. Essential background for understanding WELLBY's theoretical foundations.
- This Nature article by Frijters et al. presents the WELLBY framework and its application to policy evaluation. Key reference for understanding how WELLBYs are intended to be used.