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Trend following
Is the four-week rule the same thing as Turtle Trading?
Four-week rule · Donchian 4-Week Rule
What it bets
A four-week high or low is enough to say the trend has changed sides.
How the rule is written
Richard Donchian's weekly rule: go long when price breaks the high of the past four weeks, and go short when it breaks the low of the past four weeks. The old position reverses when the signal on the other side appears. It is usually never flat.
When it fails
In a range that keeps repeating, the four-week high and the four-week low get taken out in turn. Each reversal loses.
Do not confuse it with
The turtle short system is close to 20 trading days, but the turtles have two systems, can be flat, and size from volatility. The four-week rule is the earlier one, and it stays in the market.