Flags and pennants look simple: a sharp impulse, a tight pause, then continuation. In live books they fail often enough that process matters more than pattern recognition alone.
The impulse must be real
A flag without a clean prior impulse is just a rectangle. Measure impulse length and angle. Shallow drifts rarely justify continuation trades with wide targets.
Cost of false breaks
Place invalidation beyond the opposite side of the flag, not “just under the breakout bar.” When false breaks are frequent — thin lunchtime liquidity, news windows — cut size or skip the setup class entirely for that session.
Journal the miss
Record whether the failure came from recognition error or from execution inside a hostile window. Pattern traders improve faster when they separate those two failure modes.