The Plus-Minus stat in Lunacy

[Jared Russell]

I've been trying to come up with a good statistic with which we can approximate the aggregate of the various abilities of each robot this season. It is a hard problem because of the many different approaches to this years' game. I think we will see fast scoring bots who falter, and simple drivers that win blue banners. But everyone has one goal in mind: to maximize the differential between points scored and points allowed.

In hockey, there is a somewhat obscure stat called "Plus-Minus" (+/-) that attempts to quantify the disparity between the number of goals a team scores when a player is on the ice (+1 for each) versus the number of goals a team gives up when the same player is on the ice (-1 for each). If a player is +20, then he has been on the ice for 20 more goals for than against.

We could definitely do this for Lunacy. "Plus" is the amount of points a robot scores in a match. "Minus" is the amount of points scored in that robot's trailer. This stat would help you do apples to oranges comparisons (shooters vs. dumpers vs. pushers) to figure out who can score, who is good at avoiding being scored on, etc. With a little cleverness, you can even compute a normalized +/- that takes into account the opponents (a team who faces a lot of tough teams and emerges +5 has done better than a team that goes +15 against cupcakes).

All we would to do is assign a scout to each team in each round. Simply count the number of points scored by and on each team, and fill out a table. Divide the sum of each team's rounds by the number of rounds and you get a "+/- per round" stat that should paint a pretty clear picture about the robot's performance.

Is this stat perfect? Of course not. <G14> will affect the stat, to be sure. And teamwork is not fully acknowledged (e.g. I push this bot into the corner so you can dump into it, but I have scored no points myself). But I think it might be the best - if not simplest - representation (along with Win/Loss records) to score the robots of Lunacy.

How do the scouts of Chief Delphi feel about this? Is this something worth pursuing on a collaborative, cross-regional level?

-Jared

[Brandon Holley]

I like the idea...+/- in hockey is a VERY useful stat that tends to say a lot about the team play of an individual player.

Where this could get confusing in scouting is just the simple act of counting the balls that are being scored. Even with 1 person per robot/trailer, I could see numbers being miscounted. This doesn't mean this stat shouldn't be used (I'm sure most good scouting teams will do this exact thing, not all will call it "plus/minus") I think its just worth noting that the numbers you count for this may not be fully accurate on some occasions.

[Enigma's puzzle]

i think you are right the only problem is summoning up the "man"power to do it i know my team could never get 6 people for every match, at every competeition.

[Ryan Caldwell]

our scouting team will be taking into acount +/- for sure, i think the team effort (blocking in so partner can score) will be huge as well, and diversity in plan of attack will also be on the top of our lists

So basically you want Dennis Wideman for an alliance partner

[Bongle]

You could probably do a reverse-OPR as well. Rather than basing the OPR matrix on the sum of your alliance's scores, do another run that uses your opponent's score. That would give you the average amount that your team contributed to your opponent's score. Subtract reverse-OPR from forward-OPR, and that could get you a mathematical estimation of your +/- score without having to sit in the stands for 3 days at every regional.

What is OPR? It's a lot like simply taking your team's average score and dividing by 3, but a bit more complex and accurate. Do a search for it, there's a couple decent explanations. It is good because it can ferret out teams that just got carried along by good partners and didn't actually contribute to their high scores (something that a simple average cannot detect).

[Jared Russell]

Originally Posted by Brandon Holley

I like the idea...+/- in hockey is a VERY useful stat that tends to say a lot about the team play of an individual player.

Where this could get confusing in scouting is just the simple act of counting the balls that are being scored. Even with 1 person per robot/trailer, I could see numbers being miscounted. This doesn't mean this stat shouldn't be used (I'm sure most good scouting teams will do this exact thing, not all will call it "plus/minus") I think its just worth noting that the numbers you count for this may not be fully accurate on some occasions.

The way I would envision it is that a scout would look only at the points scored BY a robot during the round. Counting the points in its trailer is probably easiest after the round, when the field reset crew is removing the game pieces.

And yes - there would be some margin of error. The hope is that it will be fairly slim compared to the amount of "good" information.

[Brandon Holley]

Originally Posted by Abwehr

The way I would envision it is that a scout would look only at the points scored BY a robot during the round. Counting the points in its trailer is probably easiest after the round, when the field reset crew is removing the game pieces.

And yes - there would be some margin of error. The hope is that it will be fairly slim compared to the amount of "good" information.

How do you account for which robots scored which balls into which trailer? Thats going to be the essence of scouting this year.

[Jared Russell]

Originally Posted by Brandon Holley

How do you account for which robots scored which balls into which trailer? Thats going to be the essence of scouting this year.

DURING the match you watch a robot to see how many balls it scores.

AFTER the match you can watch as the balls are removed to see how many points have been scored in its trailer.

[MrForbes]

also, which Payload Specialists scored which balls in which trailer? I think we're going to see quite a variety in human scoring ability also.

[Jared Russell]

Originally Posted by squirrel

also, which Payload Specialists scored which balls in which trailer? I think we're going to see quite a variety in human scoring ability also.

That would certainly need special consideration if this method is used.

[Tom Line]

A very simplified and perhaps more accurate version of over/under (and closer to the NHL version) would be to simply take your team score and subtract your opponents score.

This would, of course, be subject to issues around teams scoring on themselves to prevent to large a win, but it would certainly still be valid considering how rare that will be.

In NHL, it's not your personal goals vs. how many is scored on you - it all goals scored while you're on the ice by your entire line... very similar to this situation.

So you only need to grab the final scores and the robots involved in each match to calculate it.

[newyorkjr]

Uhh...do you realize how hard that strategy will be to implement? Traking which balls go where and making sure that the ones are shot and picked up and delivered and robots blocked and blocking shots and... . That and there are a bunch more ways to do well in a competition rather than just scoring. What robots that you want on your team will entirely depend on the strategy that your team wants. So its a good idea...but needs some tweaking for each team.

[Rizner]

I think if you have this, you should also have another option or box that says this robot, instead of (or in addition to) shooting or dumping, plays defence, feeds to human player, helps with offensive maneuvers (trapping to help alliance score), and other things like that. If they feed to human player, how effective was their human player and how many balls did they feed them (scored 13/18 balls?). If they help with offensive maneuvers, how long did they hold, and was it long enough? Also, did they have penalties for this or that?

Just some ideas.

[RMiller]

Originally Posted by Tom Line

In NHL, it's not your personal goals vs. how many is scored on you - it all goals scored while you're on the ice by your entire line... very similar to this situation.

Just for the sake of complete accuracy, in the NHL, the +/- is only affected when both teams are at full strength or the scoring team is shorthanded.
The shorthanded part fails a bit because the robots would still expect to score in a 2 v 3 game. I would suggest, if a robot didn't show up for a match, then the difference would not be counted.

[David Brinza]

Want some more complication?

How about (as Tom Line suggests) teams that intentionally score in their own trailer (i.e. for their opponents) to avoid the dreaded 2x or 3x SUPER CELL withholding rule <G14>?

Would you ignore self-inflicted scores or count them as +'s??

Arrhhh...