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LESSONS

How people fool themselves with charts

Log scale, overfit models, survivorship bias and morning-after narratives. Learn the traps so the dashboard informs you instead of flattering you.

5 MIN READ
A stack of five ways charts mislead: scale, overfitting, survivorship, hindsight narrative, and hidden leverage.
LEVEL · Intermediate
IN THIS LESSON · 8 OF 8
BY THE END YOU WILL BE ABLE TO ANSWER
  • Why does the log scale matter for bitcoin charts?
  • What is the test of a price model?

Then prove it: a 2-question quiz. The lesson marks itself complete at 100%.

The dashboard gives you dozens of charts and the ability to overlay anything on anything. That is power, and power to mislead yourself. Five traps.

1. Linear versus log

On a linear scale, bitcoin's history looks like a vertical cliff and every past cycle looks flat. On a log scale, each cycle's percentage moves are visible and comparable. Neither is "right"; know which you are looking at and why it feels the way it does. The dashboard lets you toggle.

2. Overfitting

Any curve can be fit to any history with enough parameters. Rainbow charts, power-law corridors and stock-to-flow all fit the past. Fitting is not forecasting. The test of a model is its out-of-sample predictions, and most bitcoin models have failed theirs.

3. Survivorship

You hear about the indicator that called the last bottom. You do not hear about the hundred that did not. Indicators that worked three times are not proven; they are undefeated with a small sample.

4. Narrative after the fact

Every morning, the news explains yesterday's move: "bitcoin fell on ETF outflows", "bitcoin rose on rate-cut hopes". These are written after the price moved and would have been written the other way had it moved the other way.

5. Correlation on the overlay

Overlaying M2 or the S&P on bitcoin will often look convincing. Two things that both go up over time will correlate. The dashboard's overlay tool is for asking questions ("do these move together in this period?"), not for proving causes.

The habit

Use the data to understand what happened and where things stand. Be suspicious of anything that tells you what happens next, including your own instinct after you have looked at a chart for an hour.

CHECK YOURSELF
1/2 Why does the log scale matter for bitcoin charts?
2/2 What is the test of a price model?
pick an answer for each question
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