Understanding Scenarios
What is a scenario?
Section titled “What is a scenario?”A scenario is a named set of actuarial assumptions applied to a demographic model. ScenarioPulse lets you run multiple scenarios and plot them together on one chart — the “fan of forecasts” — to see how different assumptions drive different outcomes.
Parameters
Section titled “Parameters”| Parameter | Description | Default |
|---|---|---|
| Scenario | The base assumption set. ru_baseline uses Russia’s official reference data. |
ru_baseline |
| Base year | The year the projection starts. | 2020 |
| Horizon year | How far into the future to project. Must be after the base year. | 2050 |
| Sex ratio at birth | Male births per female birth. Affects the long-run age and sex composition of the population. | 1.05 |
The fan chart
Section titled “The fan chart”Each Run adds a new scenario to the list on the left and a new pair of lines on the chart. You can:
- Show/hide a scenario using the checkbox next to its name.
- Remove a scenario with the × button.
- Save a scenario to your account with the ↑ button (sign-in required).
Scenarios accumulate until you remove them or reload the page. If you are not signed in, scenarios are stored in your browser’s localStorage and persist across page reloads.
How the model works
Section titled “How the model works”The engine runs three sequential steps:
1. Demographic projection
Section titled “1. Demographic projection”Starting from a base-year population pyramid (age × sex), the engine applies annual mortality rates, fertility rates, and net migration figures to project the pyramid forward year by year.
2. Beneficiary projection
Section titled “2. Beneficiary projection”A coverage profile (share of recipients by age and sex) is applied to the projected population to estimate the number of pension recipients per year.
3. Financial projection
Section titled “3. Financial projection”Average benefit size and indexation assumptions are applied to compute total annual payouts. The result can be expressed as a share of GDP using a macro reference set.
Assumptions as reference sets
Section titled “Assumptions as reference sets”Each assumption (mortality, fertility, migration, recipient share, benefit size, indexation) is stored as a dated reference set. A scenario selects one reference set per assumption. Changing a single assumption while keeping all others fixed isolates that assumption’s effect on the outcome — which is exactly what the fan chart visualizes.