Educational information, not individual financial advice.
Every projection in Horizons sits on a specific methodology — deterministic math for the baseline, Monte Carlo simulation for scenario analysis, and a scoring framework for summarizing plan quality. Understanding how these work helps you read your own forecast honestly.
Deterministic vs probabilistic forecasting — the difference between "here's what happens if returns average 7%" and "here's what happens across a thousand scenarios."
Monte Carlo simulation — what it is, why it matters, and how to interpret the output.
Percentile bands — how to read fan charts and what the shaded regions represent.
Correlated market factors — why Horizons doesn't model asset classes as independent random variables.
Risk of ruin and success rates — the bottom-line survival metrics for retirement plans.
The readiness score — how Horizons scores your plan from 0–100 and what the components mean.
If you've looked at your Horizons forecast and wondered what the shaded percentile bands really mean, start with "Reading Percentile Bands." If you're curious why Monte Carlo matters more than average-case projections, start with "Deterministic vs Probabilistic Forecasting." If you want to understand your Retirement Readiness score, read "Reading the Readiness Score."
Unlike most retirement calculators, Horizons runs a full Monte Carlo simulation by default — 200+ trials with correlated market factors, year-over-year volatility, and full portfolio interaction with your specific plan. The readiness score, percentile bands, and risk-of-ruin numbers in your dashboard all come from this simulation. The articles in this section explain what those numbers mean and how to use them.
A forecast shows a single projected net-worth line into the future. How should you read it?