Joseph,
As for an explanation of (roughly) what VDC is measuring, you can find previous discussions over the years using the
Google Site Search (website menubar, left side) and enter a search term like 'VDC explanation'.
You can also read what Doc Sartin wrote about its evolution from the Entropy days in a 2 part article beginning in
Follow Up 76 Page 64 'Futureworld ...' and continuing in
Follow Up 77 'Success and Profit for the 21st Century: a Whitepaper'.
VDC is Velocity relative to Deceleration (or vice versa) - simply: how much or little was the horse slowing down (decelerating) over each segment of the race relative to the velocity in that segment and the relative Pace of the Race overall. VDC only measures the paceline(s) you designate for the horse, and does not include 'class' measurements of race conditions or competition levels: it includes only velocity/energy derived info from a given single race.
Thus, you must still (always) take care to represent the horse from an appropriate line or lines (e.g. energy distribution showing on the E/L graph is not atypical); the horse is in a current form cycle or you are using consistent judgements about horses returning to a new form cycle - in other words: all analysis you would make anyway to determine if the horse is a contender to win or finish in the money today (see many discussions recently re Paceline selection).
If you have chosen a consistently applicable paceline, VDC will indeed show horses who have decelerated least in the 3rd fraction while also having run against a fair 2nd call and 1st call pace of race. You will see many corollaries with other readouts which include F3, for example TS+F3 (segments screen), especially where the VDC rank is 'out of order' with the BLBL rank. A simple Deceleration measurement like DEC (F3/2nd Call velocity) usually ranks inverse to the 2nd call rank - that is, the slower the horse was gong to the 2nd call, the less it decelerates in the 3rd fraction - which isn't exactly a newsflash, or even useful much of the time.
The real interesting info is when a horse (relative to its competitors today) decelerates less, late, relative to having had a bit of speed earlier (1st and especially 2nd calls). That mix of deceleration relative to velocity and tempered by overall Pace of Race is the 'secret sauce' of VDC. But you MUST perform other analysis about current form cycle and suitability to race conditions today to know whether your representative line for the horse (e.g. one of the last 3 lines) is fair today.
I am not providing the specific formula for VDC (and I know you are not asking for it
), but the above general concepts plus Doc's more theoretical description and examples in the above noted Follow Ups are all you really need to know. I don't know why
light behaves like
both a wave
and a particle, but I do know it helps my cell phone work.
If you study some of the recent reports by
Rmath, you will find that Top 2 and ties VDC ranks together with Composite Speed Ratings (CSR) from consistently chosen and representative pacelines, provide some steady sets of contenders from which to seek value.
Hope that helps!
Ted