Episode 545: The Ins And Outs of Monte Carlos And Back Tests, The Golden Ratio For Radiologists, Broker Boilerplate, And Portfolio Reviews As Of October 16, 2026

In this episode we answer emails from Dave, Bob, and Waldo.  We discuss how Monte Carlo simulations differ depending on their basis and how they differ from historical back-tests, the problem of trusting retirement calculators without understanding the assumptions inside them and choosing the correct assumptions, why the Golden Ratio portfolio is built for bad decades, and why a scary brokerage warning screen is often just strategic butt covering and marketing.

And THEN we our go through our weekly portfolio reviews of the eight sample portfolios you can find at Portfolios | Risk Parity Radio.

Additional Links:

Jesse Cramer Best Interest Podcast Episode 134:  Even Financial Advisors Misunderstand Monte Carlo Retirement Analysis (E134)

Yours Truly on Best Interest Podcast:  Are You Hoarding, Hustling, or Harvesting in Retirement? - E144

The Four Quadrant Model Exquisitely Explained With Illustrations Inspired By Vermeer:  The Four Quadrant Wealth Atlas.pdf - Google Drive

Four Quadrant Model Video:  Understanding Correlations and Diversification Using the Four Quadrant Model

Minimize Your Miss Article About The Golden Ratio Portfolio:  Minimize Your Miss – Portfolio Charts

Breathless Unedited AI-Bot Summary:

One retirement tool says you’re fine. Another says you’re headed for disaster. If you’ve ever run a backtest, then hit “Monte Carlo” and watched your plan implode, we get why that feels like whiplash and we also know it’s usually explainable.

We walk through a listener’s withdrawal-rate question and break down the real reason these results diverge: the construction of the simulation. We explain parameterized Monte Carlo (assumed returns and standard deviation on a normal distribution) versus historical Monte Carlo (scrambled real return data), why fat tails and skewness matter, and how limited datasets for assets like international stocks or REITs can quietly distort the numbers. We also share a simple rule for better decision-making: stop hunting for a “perfect” portfolio in a calculator and start comparing Portfolio A to Portfolio B across multiple tools until the relative story stays consistent.

From there, we connect the math to portfolio design. We talk about why worst-case decades drive safe withdrawal rate research, why a decumulation portfolio has different goals than a stock-heavy accumulation portfolio, and how the Golden Ratio approach fits into a four quadrant model across inflation and growth regimes. Then we tackle a very practical worry: Fidelity’s scary designated investments agreement screen when buying a gold ETF like GLDM and why that warning is often more about liability and business model than unique risk.

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