A retracement level is only as useful as the swing it measures. In our Bangkok classroom we start every Fibonacci exercise by naming the impulse: where the move began, where it ended, and whether intervening candles still belong to that impulse.
Students often reach for the most recent high and low on the screen. That habit produces neat-looking ratios that have little relationship to how price actually travelled. We ask for three checks: clear displacement, a pause that does not erase the impulse, and a destination that other traders would also recognise.
Once the anchors are agreed, 38.2%, 50%, and 61.8% become conversation starters rather than predictions. The class then compares those levels with prior structure so the ratio is never used in isolation.