I look at the rate of change. But the point or percentage change is too misleading because things get to out of whack on the close.
I follow them in groups
spx vs indu vs ndx
nya vs comp
oex vs rut
it comes naturally after a while.
a fast spx and a medium indu and a slow ndx is usually a weak move. Timing the bet the spread will narrow however is very difficult for me, and I ususally just use the spread for evaluating strength.
