performance index?

[Rick Johnson 29]

How do they come up with this number?

[mikendzel]

Finish percentage.  E.G. If you finish 3rd out of 4 entries, your performance index is .250; like a batting average.

[catman]

Man I sure have been away a couple years so my memory may evade me a bit,I think you just meant .750?

[MELK-MAN]

huh?
maybe the lower 75th percentile.. but your PI would be .250 if you finished 3rd in a race of 4.

[catman]

AH- I wasn't sure,thanks ,Melk Man    Should,nt have been so sure of this ( )

[kl3640]

Finish percentage.  E.G. If you finish 3rd out of 4 entries, your performance index is .250; like a batting average.

Not exactly...the wrinkle is that the last place rider does get some PI!

Given that the last place rider finishes with a PI for that race >0, therefore:

T = riders on grid
P = Finish position
A = Riders ahead of your finish position

Therefore:

A = P-1

Therefore:

PI = ( ( (T-(P-1))/T) * 1000

OR

PI = ( (T-A)/T) * 1000

In the example where there are 10 riders on the grid and I finish 5th, my PI would be:

PI = ( ( (10-(5-1))/10) * 1000 = 600

Or, 10 riders, 1st place finish:

PI = ( ( (10-(1-1))/10) * 1000 = 1000

Or, 10 riders, 10th place finish:

PI = ( ( (10-(10-1)/10) * 1000 = 100

Or, in your example:

4 riders, 3rd place finish:

PI = ( ( (4-(3-1)/10) * 1000 = 500

Also, CATMAN, if you're looking to get caught up on the happenings during your absence, maybe try the Search feature, as much of this stuff has been discussed in prior threads.

[mikendzel]

kl3640 was correct!!! 

Here's what the rulebook stated when the formula was in it:
"Section 8.  Specifically 8.2.

There are double points weekends which count for twice the points.

Performance index =

(# of riders - number of riders who finished ahead of you) / number of riders * 1000

For intance, if you came in 3rd in a race of 10 riders,

10 - 2 = 8
8/10 = .8
.8x1000 = 800

Your overall performace index is an overall average of your class averages. "



*  His forumla in the last example was incorrect for those of you that were confused by that.  He meant  PI = (((4 - (3-1))/4) * 1000 = 500

[MELK-MAN]

AH- I wasn't sure,thanks ,Melk Man    Should,nt have been so sure of this ( )

no prob!..lol.. you should see the riders at the end of the season scrambling around with scratch pads and calculators trying to determine who they have to beat and by how many places to keep a point lead for a championship..then they pull the hair out by the roots after forgetting to factor in a performance index, but then forgetting the performance index of that round factors in as well. Yea, that was me.

[kl3640]

kl3640 was correct!!! 

Here's what the rulebook stated when the formula was in it:
"Section 8.  Specifically 8.2.

There are double points weekends which count for twice the points.

Performance index =

(# of riders - number of riders who finished ahead of you) / number of riders * 1000

For intance, if you came in 3rd in a race of 10 riders,

10 - 2 = 8
8/10 = .8
.8x1000 = 800

Your overall performace index is an overall average of your class averages. "



*  His forumla in the last example was incorrect for those of you that were confused by that.  He meant  PI = (((4 - (3-1))/4) * 1000 = 500

Oops...the hazards of Ctl-C + Ctl-P :)

One thing that should be pointed out is that I've been told (Melk-Man, feel free to chime in here) that Overall PI (as per section 8.2 of the rules: Your overall performace index is an overall average of your class averages.) is actually a straight arithmetic mean of the PI's of each of your classes, without respect to the # of events run in each class.

Therefore, if you were to run 4 classes all season, then run a 5th class in the final round of the season, the PI for that 5th class would get averaged in to your overall PI the same as those other 4 classes.  Doing so could of course help you or bite you, depending on how you do in that 5th race.

[MELK-MAN]

Exactly Vas,
you could run 1 class all SEASON and win every race.. PI of 1000. Then you decide "hey, ill run race-X" and you finish dead friggin last after crashing on the start.
1 race.. PI "0".. that one race for that one class is figured in with as much weight to your OVERALL performance index as the class you won all 10 races in.. 1000 + 0 / 2 = 500. YOur overall pi is 500 even though you won 10 races in 1 class and finished dead last in only 1 race.

[Rick Johnson 29]

Thanks for all your help.Now I understand.It was confussing when I read about it in the rule book.

[catman]

Vas Quote-
Also, CATMAN, if you're looking to get caught up on the happenings during your absence, maybe try the Search feature, as much of this stuff has been discussed in prior threads

I have been just basically reading much lately,going backwards through the previous pages of threads.  I just answered originally too quickly and this topic wasn't high on my list quite yet of things to ponder,since its hard to collect any points without being on a grid for a couple seasons- I am glad ,to have it clearly explained,and it is a great topic most would agree ,for sure. Thanks much- congrats on your  vas? (and Greg's) efforts,I am still reading through the important stuff,right? Cat