Success Rate | Timeline Help Centre

Summary

• Success Rate measures how often a financial plan succeeds across historical scenarios.
• A plan is considered unsuccessful if it runs out of money or fails to meet the desired legacy.
• Calculated as the percentage of successful outcomes across all scenarios tested.
• Based on historical simulations using real market returns and inflation data.
• Rounded to the nearest 1% in Timeline Planning.
• Capped at 99% to avoid implying certainty or guarantees.

Description

The Success Rate in Timeline Planning is a core metric used to evaluate the robustness of a financial plan under uncertainty.

Rather than relying on a single projection, Timeline tests a plan against hundreds or thousands of historical scenarios—each representing different sequences of:

• Market returns
• Inflation environments
• Economic conditions

A scenario is considered a failure if:

• The portfolio runs out of money during the plan period, or
• The ending balance falls below the desired legacy target

The Success Rate then answers a critical client question:

“How confident can I be that this plan will work?”

How It’s Calculated

The Success Rate is calculated as:

• Total number of scenarios tested
• Minus the number of failed scenarios
• Divided by total scenarios
• Converted into a percentage

Behavioural Design Considerations

From a product and behavioural finance perspective, Timeline intentionally applies two important rules:

• Rounding:
  • Success rates are rounded to the nearest 1% to keep outputs simple and client-friendly.
• Capping at 99%:
  • Even if a plan succeeds in all tested scenarios, the displayed success rate will never exceed 99%.

This avoids creating a false sense of certainty, reinforcing that all financial plans carry some level of risk.

Example

Suppose you analyse all 30-year historical scenarios from January 1900 to December 2018:

• Total scenarios: 1,068
• Failed scenarios: 79

Applying the formula:

• Successful scenarios = 1,068 − 79 = 989
• Success Rate = (989 / 1,068) × 100 ≈ 92.6%
• Displayed in Timeline as: 93% (rounded)

This means:

In 93% of historical scenarios, the plan successfully sustained withdrawals and met the legacy goal.

Conclusion

The Success Rate is a powerful, intuitive metric that brings probabilistic thinking into financial planning.

By grounding outcomes in historical data and framing results as a percentage of success, it enables advisors to:

• Quantify risk and resilience
• Communicate uncertainty clearly
• Guide clients toward more sustainable decisions

Combined with Timeline’s behavioural safeguards (rounding and capping), it ensures clients remain informed, not overconfident—which is critical for long-term planning success.