Both VEL and RSX measure market momentum.
VEL measures momentum direction and speed accurately to scale. If bar-to-bar price
changes double in size, VEL's chart will double in size. In other words, VEL provides true momentum.
This makes VEL not useful for thresholding, such as when you want to trigger a
BUY/SELL when VEL crosses over/under a (non-zero) threshold value. The reason is because the threshold will require
almost continuous readjustment as the magniture of price changes grows/shrinks over time. However, this property is
very useful in divergence analysis, where you want to accurately compare price turning point values to momentum turning
point values. CLICK HERE for a graphic example of this use in divergence analysis.
RSX, in contrast, measures momentum direction and **quality**, not speed. If trend
quality is pure (i.e. having tiny reversals) then RSX signal is strong. If quality is weak, such as when a trend is
congesting into a trading range, then RSX signal becomes weak. This makes RSX ideal for showing market reversals and
the demise of trends weakened by excess volatility.
RSX is also bounded between the range of 0 to 100. In contrast, VEL is unbounded
and can have any value. This scale-invariant nature of RSX makes it suitable for thresholding, as the threshold level
does not need to change over time, as it would for VEL. Consequently, you can define BUY and SELL zones with RSX,
whereby a SELL order is never executed when RSX is above the BUY ZONE threshold level, and a BUY order is never
executed when RSX is below the SELL ZONE threshold level.