The Start Date Sensitivity chart studies the past and future returns of a portfolio at various points in time to illustrate how actual returns varied from expectations. Use this to study the dependability of a portfolio over time, to find a stable asset allocation that reliably met its goals, and to serve as a reality check before trusting a tempting but potentially deceptive historic average with your life savings.
Chart
Modify the inputs in black to update the image /// Instructions
If the chart doesn’t load after a few seconds, refresh your browser.
Click to open
The interactive charts are sophisticated tools that push the limits of some mobile devices. If it doesn’t work, don’t give up! Visit this page on a laptop or desktop for the full experience.
Create custom charts with your own data ⚒️
Overview
For each year on the start date sensitivity chart, the calculator looks both backwards ten years and forward ten years and reports the inflation-adjusted CAGR for both numbers. The red line tracks the backward-looking return and the blue line tracks the forward-looking return. The vertical bars track the difference in those two numbers — blue bars mean that the next ten years were better than the previous ten years, and red bars mean the opposite.
Studying the variety of differences in those two numbers gives you a very good idea for the stability of returns over time. The closer the two lines, the less sensitive the portfolio is to backtesting start date bias.
Featured Walkthrough
Calculations
Luckiest
The Luckiest datapoint is the best return difference between the forward-looking return and the backward-looking return. For reference, the best improvement is visually recognizable as the longest blue column.
Unluckiest
The Unluckiest datapoint is the worst return difference between the forward-looking return and the backward-looking return return. Imagine purchasing a fund based on a high previous 10-year return but personally receiving this amount less than that number per year for the next ten years after you bought it. Talk about disappointing!
Start Date Sensitivity
This is the difference between the luckiest and unluckiest datapoints. Think of it as the spread in happiness relative to expectations between all of the different investors that bought the portfolio over time. I see it as a simple quantitative way to help you compare the relative dependability of two portfolios. Smaller numbers have historically been better at meeting investor expectations than larger numbers, with less timing luck required to get the advertised return.
Discussion
Join the conversation
Articles
Insights that reference Start Date Sensitivity
