Method:
- Define a swing objectively, for example a move of at least 15 pips on M5 without a pullback of more than 3 pips.
- note the largest retracement expressed as a share of the swing.
- Compare the distribution with what you'd expect without any special level.
Practical point: even without a special level, retracements of 50% to 70% are common for many swings, so a zone may still be useful as a rough entry area.
Record the sample size and period with the result. A few dozen swings won't separate a real cluster from noise, so collect a few hundred before drawing conclusions, and test separately for trend and range days, because pullback depth often differs between them.
Has anyone tested Fibonacci levels with a clear method?