This probably deserves more than a quick answer, but I would say this-- even if all your variant decisions are right, there is play in your figures WITHIN a race because of rounding off (and general innaccuracy) of charting of ground loss, and some small rounding off of the beaten length info. The wind doesn\'t matter that much unless you make unwarranted assumptions about the underlying data and formulas being rock solid, and make dogmatic decisions, rather than use the previous histories of the horses.
Race to race, the more data (solid figure histories) you have, the more solid the figures you assign. In other words, if you have a race with lots of first time turfers, there is more of a chance of getting it wrong, and if it\'s the only grass race that day (or after a rain), it\'s even tougher. You could come up with all kinds of degrees of gray when it comes to this-- the other extreme would be a BC grass race, where you have solid figure histories of horses who run in a tight range, and ground looked at by more than one guy.
I can\'t really give you a range or percentage on this, but a figure can certainly be off by a half point either way within a race, even if you get the variant right. That may change when they go to electronic tracking in the future, but for now it\'s true for everybody.
