[FRC Blog] "Standard District Points System for 2015"

[Rachel Lim]

Originally Posted by MasterMentor

You both forgot the Ceiling Function.

Thanks for the catch--I believe it's fixed now, but I don't know what the results should look like, so I can't really check. Please let me know if you catch anything else.

The same link should work: http://www.wolframalpha.com/widgets/...2fb3bb85e071b4

[cadandcookies]

Originally Posted by MasterMentor

What, you mean like in Frank's Blog on Kickoff Day?

http://www.usfirst.org/roboticsprogr...ct-points-2015

Thanks for catching that. Like I said, I'm not in a region with districts, so I tend to miss some of this stuff. Frankly given that, I'm even more confused by some of the complaints in this thread.

[MasterMentor]

Originally Posted by Zebra_Fact_Man

First takeaway: Why was the QS capped at 22 pts instead of the previous 24?

In the GameSense interview, Frank mentioned that only 0.6% of all teams scored 24 points last year. I guess it would have been nice to have a perfect comparison to last year, but ignoring the 0.6% doesn't seem devastating to me.

Originally Posted by Zebra_Fact_Man

Also, why is the minimum 4 instead of 0?

In the summary document, it says "typically-sized district events" would have a minimum of 4 points. Though, in the explanation document the tables show that at about an event size of 55 the minimum goes from 4 to 3. Using Rachel Lim's district points widget, it looks like 3 is the minimum going all the way up to a tournament size of 1,000. If you look at the explanation document, the range scale in the formula is 10, but the gain factor at the end is 12; that says to me the formula is built to never go below 2 points, and because of the nature of the Inverse Error Function (going to infinity at the limits and all) and the use of the Ceiling function, you will never go below 3 points period.

Though, I must admit, it would be a crushing blow for a team to show up at an event and get no points whatsoever. Even if they don't have aspirations of making it to the District Championships, getting a goose-egg is deflating.

[Ian Curtis]

I think a one sentence version of Danny's white paper should really ought to go into the manual with a graph (and a link to the white paper!). This function is going to be needed to be explained several thousand times this season and teams/volunteers/the public seeing math as a scary black box is good for no one.

Something along the lines of "This function assumes teams are approximately normally distributed, and awards points based on rank. The #1 seed will receive 22 points, the middle of the pack ~12, and the lowest ranked teams ~4.

Then a plot for a 40 team event, with rank on the x axis and points awarded on the y.

[AGPapa]

Originally Posted by artK

The answer to the first question is because, even in a WLT system, perfect 24s are pretty rare. In MAR, according to this, 22's have only been done twice, and in theory a 24 should have only happened once at this point. (Though it would be interesting to see what a difference a WLT would have on this game on the rankings). More matches per team make it harder to score a perfect record.

To clarify, 23's have only been done twice. 22's are a little more common.


Oh, and I made a spreadsheet showing how the QS points will be distributed by rank for every MAR event. The MAR events are all similar in size this year, so it doesn't change much event by event.

[MasterMentor]

Originally Posted by Ian Curtis

This function is going to be needed to be explained several thousand times this season and teams/volunteers/the public...

Really? You think Volunteers and the Public care about the District Points System beyond what can be found in a, "Rank/Points" chart?

I'm glad FIRST didn't just publish a "bunch of tables" and actually showed us what's behind the scenes. It gives more credibility to the data in my opinion.

[MikeE]

Originally Posted by Thad House

However, the top teams are not usually the ones where 5 points makes a difference, so it most likely would not have much of an actual effect on the top.

This is the key point (pun intended) in the discussion^*
The small difference in points for teams at the top and bottom of the distribution make little impact on progression through the season. For example, in New England last year every team with a record of better than 10-2-0 at either of their scored events ranked in the top 10 teams going into the District Championship.

However running the 2015 rank-based points model on 2014 New England results shows that there would have been only 1 change to the teams invited to the District Championship. So it doesn't seem to make much difference in the middle of the pack either.

One small effect of the change is that teams are no longer penalized directly for disqualification or not being inspected in time for the qualifications matches. The indirect penalty of a reduction in average score may be larger.

Finally the use of the ceiling function means smaller events have a slightly higher expected points total per team, but this is minuscule in comparison to the huge seeding/playoff points advantage at smaller events.

^*although I personally enjoy any work incorporating a statistical model, so props to Danny!

[SoftwareBug2.0]

Originally Posted by lopsided98

Here is a quick calculation script I threw together. It requires Python 3. The inverf implementation is not mine and comes from here: http://johnkerl.org/python/normal_m.py.txt

I might extend it to generate tables in the future, but it works well enough for now. Let me know if you find a problem with it. It is a .txt because CD doesn't allow .py files.

I've turned the output of this program into a series of tables. Each file in the archive corresponds to an event size, and in each file each line lists a ranking and the number of points that is.

A quick note on the script: I have not verified the script and the first line of it says to use python 2.7 rather than version 3, so perhaps take these numbers with a grain of salt.

[Qbot2640]

We're confirmed to enter the District System next year (NC) so I'm trying to understand the math now. After the explanations of the formula - I get that...but I'm not sure I get how the Alliance Captains and Draft Order points compare. Would the first alliance captain and their first pick both get 16 points?

[Mark McLeod]

What better peer recognition could there be than being the #1 choice of the top ranked team?

[MooreteP]

I love math.

[GaryVoshol]

Yes, Alliance Captain 1 and their first pick both get 16 points, #2 each get 15 ... down to #8 captain and pick both get 9 points.

Alliance Captains are based on the position they hold after picking is done (e.g. if #1 picks #2, the original #3 captain becomes alliance captain #2 and gains a point).

Then on the way back up the serpentine draft, 2nd pick (3rd alliance members) for alliance #8 gets 8 points, #7 gets 7 points ... #1 alliance (last pick) gets 1 point.