A whipsaw occurs when a timing signal fires, a trade is entered, and price then immediately reverses — leaving the trader worse off than if they had done nothing. The term comes from the two-handed logging saw: you get cut on the push and then again on the pull. In markets, a whipsaw means buying a breakout that fails, or selling a breakdown that snaps back.
Whipsaws are the central cost of mechanical timing strategies. Every moving average crossover, every RSI threshold, every sentiment-driven signal will generate false positives in certain market conditions — particularly in low-volatility, sideways, or choppy ranges where trend-following signals thrive on false hope. The more sensitive a system's parameters, the more frequent the whipsaws.
There is no way to eliminate whipsaws without also reducing the number of real signals captured. The practical choice is a trade-off: wider parameters (longer moving average periods, higher RSI thresholds, slower rebalancing) produce fewer whipsaws but miss more of genuine moves. Understanding this trade-off is fundamental to evaluating any timing strategy honestly.