Explore a model’s assumptions before treating its final number as an answer.
Begin with the inputs
The Investment Lab starts with 10,000 virtual credits and three fictional buckets: cash, bonds and shares. Each scenario contains ten invented annual returns for every bucket. You can read all those inputs beneath the game. They are not live prices, historical averages, forecasts or a list of products available to buy.
Understand the annual step
The model multiplies each year’s opening value by one plus the allocation-weighted annual return. A half share allocation gives the fictional share return half the weight. The model restores the chosen weights each year without charging transaction costs. That annual rebalancing assumption is part of the experiment and would require more detail in a real portfolio model.
Change one assumption
Keep the allocation fixed and switch between Bumpy growth, A difficult decade and Drop, then recovery. Then keep a scenario fixed and change the allocation. These comparisons show how the answer depends on the assumptions. A favorable invented path cannot establish that an allocation is safe, appropriate or likely to perform similarly outside the game.
Read the limits with the result
The displayed balance excludes fees, taxes and inflation. Lowest balance means the lowest modeled year-end value, including the initial amount; it does not measure every possible loss between those points. The lab is useful for asking better questions about a model. It cannot recommend an investment or predict a personal outcome.
Try the idea in the money playground, or explore another lesson in the notebook.
