Hi Rock Steady,
I have mentioned a number of times about the importance of the Standard Deviation in our Handicapping, what you have mentioned re "chasers" gives a prime example of how one can catergorise types of runners by just using the STDev with one other Factor.
A typical "chaser" has a smaller then normal lengths beaten from winner avg(will then be overplayed by the public), but a larger spread of Race Win Times thus a wider STDev.
(So knowing this type of runner/s are in todays race gives an edge once known.)

A sidelight to these types of runners and what one should do when modelling these runners is this, what chance has this dog of running times, 2 deviations slower then his avg time then running 2 deviations quicker, in fact this type gets nowhere near the 2 deviations quicker mark maybe not even halfway.