The hybrid IFs model for forecasting health (using distal and proximate drivers) provides forecasts of age, sex and country-specific mortality rates for most of the 15 cause clusters it represents. The model within IFs for mortality in those cause clusters builds on the Global Burden of Disease (GBD) methodology, which uses mainly distal (more distant) drivers to project mortality.  IFs then extends that methodology in many cases by adding attention to a selected set of proximate drivers.
For several other causes or cause clusters (*), most of those related to communicable disease, the IFs system uses a variant of the distal driver approach, one that looks to a forecast of all communicable disease except HIV/AIDS and then subdivides that total by more specific disease type.
For still other causes of mortality (**), it uses more specialized models totally unrelated to the distal driver approach.
Cause Clusters in IFs 
- Other Group I diseases (excludes AIDS, diarrhea, malaria and respiratory infections)*
- Malignant neoplasms
- Cardiovascular diseases
- Digestive diseases
- Chronic respiratory diseases
- Other Group II diseases (excludes malignant neoplasms, cardiovascular diseases, digestive diseases, diabetes, chronic respiratory diseases, and mental health)
- Road traffic accidents**
- Other unintentional injuries (excludes road traffic accidents)
- Intentional injuries
- Respiratory Infection *
- Mental Health**
For help understanding the equations see Notation .
- Distal Driver Formulation
- Diabetes and Chronic Respiratory Diseases
- Cardiovascular Disease
- Diarrhea, Malaria, and Respiratory Infections
- Road Traffic Accidents
- Mental Health
 See Mathers and Loncar (2006) for a more complete description of GBD projection methods and rationale.
 The first 10 causes in this ordering were specific ones from Groups 1, 2, and 3, associated with a residual for the remaining causes in each group–that is, the ordering was systematic. The subsequent addition of HIV/AIDS and then of diarrhea, malaria, respiratory infections, and mental health pulled additional specific causes from the various groups and caused the ordering of those additions and the entire list to be irregular with respect to groups. At some point, we will likely re-order the causes of death into the 3 groupings.