5. Sensitivity and Uncertainty Analyses for Burden of Disease and Risk Factor Estimates
Select, organize, download, and save your choice of chapters into a single PDF file for printing and distribution. This is a free service.
Log in to view your saved custom books
Editors/Authors: Colin D. Mathers, Joshua A. Salomon, Majid Ezzati, Stephen Begg, Stephen Vander Hoorn, and Alan D. Lopez
Epidemiological studies report confidence or uncertainty intervals around their estimates. Estimates of the burden of diseases and risk factors are subject to a broader range of uncertainty because of the combination of multiple data sources and value choices.
Sensitivity analysis can be used to examine the effects of social values that have been incorporated into the design of the disability–adjusted life year (DALY). Age weight, where a year of healthy life lived at one age is valued differently from at another age, is the most controversial value built into the DALY. The discount rate, which addresses the difference in value of current versus future health benefits, also has been criticized.
The distribution of the global disease burden and rankings of various conditions are largely insensitive to alternate assumptions about the discount rate and age weighting. The major effects of discounting and age weighting are to enhance the importance of neuropsychiatric conditions and sexually transmitted infections.
The Global Burden of Disease study also has been criticized for estimating mortality and disease burden for regions using incomplete and uncertain data. Including uncertain results, with uncertainty quantified to the extent possible, is preferable, however, to leaving blank cells in tables intended to provide policy makers with an overall assessment of burden of disease. No estimate is generally interpreted as no problem.
Greater investment in getting the descriptive epidemiology of diseases and injuries correct in poor countries will do vastly more to reduce uncertainty in disease burden assessments than a philosophical debate about the appropriateness of social value
Click on the links below to read the full text.
- Discounting and Age Weighting in the DALY Measure
- Sensitivity of Burden of Disease and Injury Results to Variations in Key Parameter Values
- Sensitivity of Risk Factor Estimates to Variations in Key Parameter Values
- Uncertainty Analysis of the Global Burden of Disease Estimates
- Uncertainty Estimates for All-Cause Mortality and Life Expectancies
- Uncertainty Estimates for Regional Mortality by Cause
- Uncertainty in Disability Weights
- Uncertainty Arising from Epidemiological Estimates
- Uncertainty in the Disease Burden Attributable to Risk Factors
- 5.1 Age-Weighting Function Incorporated into the DALY
- 5.2 Effect of Age Weighting and Discounting on the YLL per Death at Various Ages for Females
- 5.3 Effect of Age Weighting and Discounting on the Male-Female Gap in YLL per Death
- 5.4 Effect on YLL per Death of Varying the Parameter Beta in the DALY Age-Weighting function
- 5.5 Effects of Changing the Discount Rate and Age Weighting on DALYs' Broad Cause and Age Composition, 2001
- 5.6 Relationship between the Rank Order of Causes of the Global Burden Using DALYs(3,1) and DALYs(3,0) in 2001
- 5.7 Relationship between the Rank Order of Causes of the Global Burden of Disease in 2001, Using Uniform Age Weights and 3 Percent Discounting and No Discounting
- 5.8 Effects of Changing the Discount Rate and Age Weighting on Global Rankings for the Top 20 Causes of the Burden of Disease, 2001
- 5.9 Effects of Changes in Key DALY Parameters on Proportion of the Global Disease Burden Attributable to Risk Factors
- 5.10 Effects of Changes in Key DALY Parameters on Proportion of the Regional Disease Burden Attributable to Risk Factors for Low- and Middle-Income Countries
- 5.11 Effects of Changes in Key DALY Parameters on Proportion of the Regional Disease Burden Attributable to Risk Factors for High-Income Countries
- 5.12 Uncertainty Ranges for Child and Adult Mortality for WHO Member States, 2001
- 5.13 Uncertainty in Average Life Expectancy at Birth, by Sex and DCPP Region, 2001
- 5.14 Sensitivity of Uncertainty Ranges to Changes in Between-Country Correlation Assumptions
- 5.15 Assumed 95 Percent Uncertainty Ranges for Disability Weights Based on Constant Variance Distribution for Logit of Disability Weight
- 5.16 Relative 95 Percent Uncertainty Ranges for Disability Weights Based on the Assumption of a Constant Variance Distribution for Logit of Disability Weight across All Disability Weights
- 5.17 Estimated 95 Percent Uncertainty in Total DALYs(3,0) Due to Uncertainty in Estimation of Disability Weights, Top 20 Causes, Low- and Middle-Income Countries
- 5.18 PAF Sensitivity to Exposure and Relative Risks
- 5.1 Standard Life Expectancies at Selected Exact Ages and Discounted YLL Due to a Death at Selected Ages
- 5.2 Implications of Variation in Choice of Age-Weight Parameter Beta on the Age-Weighting Function
- 5.3 Comparison of the Effects of Changing the Discount Rate (r) and the Age-Weighting Factor (K) on the Composition of DALYs(r, K), 2001
Effects of Changing the Discount Rate (r) and the Age-Weighting Factor (K) on the Second-Level Cause Group Composition of DALYs(r, K), 2001
(percentages of total DALYs)
Estimated Total Deaths and 95 Percent Uncertainty Ranges for Selected Causes, by Region, 2001
Estimated 95 Percent Uncertainty Ranges for YLD and DALYs Arising from Uncertainty in Disability Weights for Selected Causes for Low- and Middle-Income Countries, 2001
- 5.7 Estimated 95 Percent Uncertainty Ranges Arising from Uncertainty in Disability Weights for the Top 40 Causes of the Burden of Disease in Low- and Middle-Income Countries, 2001