To select the stocks in harmony with the market, Wyckoff selected stocks that were strong in upward trends and weak in downward trends. He believed it was futile to act against the trend. His calculation of relative price strength used the percentage changes from wave highs to lows and lows to highs of each stock versus those of the Wyckoff Waves. Those stocks that consistently outperformed in each wavein the direction of thelonger wavetrend werethe ones to analyzefurther.