Re: Offensive Power Rankings for 2008
 

Oh thats it, so the first one was an overall OPR and the last one was based only on a teams last performances? Gotcha.

Re: Offensive Power Rankings for 2008
 

My data was determined using actual scouting. Scouting was done by 2194 and 171. I have the data for every team if you want me to compile it all. This is only for Friday at Milwaukee for comparison.

Kind of interesting to see the differences.

Power Rankings
Actual

Re: Offensive Power Rankings for 2008
 

Can you post San Diego?

Re: Offensive Power Rankings for 2008
 

Nice job on the stats all of you who have been working the numbers...a thought has occurred regarding use of last regional numbers to rank teams-a stated presumption of best performance then if multiple regionals were entered doesn't take into account factors like some regionals with a higher proportion of rookie teams (translating often into higher scores by veteran teams) which was seen in Hawaii last week and Okla and Minn. earlier. Also, increasing levels of defense have shown up in some of the latest regionals as the game evolves (watch footage from LVR). Seems like an average of all performances is more representative...and the likely data source my team will use for some assistance with early scouting.

Re: Offensive Power Rankings for 2008
 

Too bad FIRST doesn't report penalties. I wonder how those are affecting these results.

Re: Offensive Power Rankings for 2008
 

Well, the head ref records penatlies for each robot during the match on a sheet, but you never see it unless you go to the "Contest the score" box.

My data comes from Lines Crossed in Hybrid, Balls Removed in Hybrid, Laps, Herds, Hurdles, and Balls Placed at the End.

Re: Offensive Power Rankings for 2008
 

Like 171/2194, 1732 recorded the amount of points a team scored per match at Wisconsin. We kept track of lines and balls knocked down in hybrid, laps, hurdlers, herds and balls placed at the end.

I ran a correlation test to see how related the two sets of data are and see how good the OPR is at predicting how many points a team scores per match. There are some assumptions/problems. First, our scouting data isn't perfect so there is some error from that. Secondly, our scouting data doesn't include penalties, but the ORP does account for them. So, when doing a linear regression, I got an R value of .7841 and an R-squared value of .6149. (A perfect relationship would have an R value of -1 or 1 and no relationship would be 0). So, while it is not pefect (not surprising) the ORP is a fairly good predictor of a team's preformance.

Re: Offensive Power Rankings for 2008
 

I agree. The OPR does do a pretty good job. Of course, hard data is nice too, but I find it really awesome that you can figure this much out with just match scores.

Re: Offensive Power Rankings for 2008
 

One reason for Offensive Power Rankings not matching reality is due to the fact that OPR’s are based on the averages of partners’ OPRs rather than actual contributions. Any deviation of a team from its ‘average’ contribution in a given match will always erroneously drive their partners’ OPR up or down.

These deviations can be large; it would not be unusual for a team to contribute 20 points in one match and then perhaps due to penalties, “contribute” -20 in the next. Given enough matches one might expect these errors to cancel each other out. However, when there is a limited number of matches (think: 8 coin tosses don’t always produce 4 heads and 4 tails) and the high degree of volatility, the error can be significant.

So while the OPR may be a good predictor, there's still no substitute for accurate, detailed scouting!

Re: Offensive Power Rankings for 2008
 

Spot on John. Congrats on the Woodie btw. You deserve it. Hope to catch up with you in Atlanta.

Re: Offensive Power Rankings for 2008
 

I asked this question earlier, but no one replied to it:

if there was a normally very high scoring team that happened to malfunction in a match where they were in your alliance, or was defended a lot in your particular round, wouldn't your score be highly skewed?

-also-

if three very very good teams were in the same round on the same team at the same time, wouldnt it also get skewed?

thanks for any input, because the OPR isnt even close to our average point contribution to our allinace that i calculated by hand after watching our regional videos, and our team hopes that teams at ATL won't rely on the OPR greatly for scouting, as it may negatively influence their decisions for alliance parings with our team, as well as many others. once again, thanks!

Re: Offensive Power Rankings for 2008
 

Of course that many things could skew the nubers. However, the law of large numbers still applies: the more and more samples you take, the more the number you're sampling appraoch its true value. So even if one matches is skewed, the average if your ten matches, or maybe more, will still be close to the expect numbers.

I think relying on any one tool too much to make a decision is a bad idea. Look, for example at what NFL teams do before they draft someone: watch game video, look at game statistics, look at the player during workouts, look at iq tests, personal intrviews, and more. Similarly, the best scouring teams in Atlanta will combine several different measurements and inputs to make their lists. I imagine they will go around talking to teams and getting an impression of their strategy, gameplanning, and experience. I bet they will have people recording matches and looking at what each team does, driver skill, performance, etc. I would guess they also watch some teams' recorded matches, especially from eliminations, to see how those teams fair when it's make-it or break-it time. A combination of these different tools is what will probably lead the eventual winning alliance captain to compile its alliance.

Re: Offensive Power Rankings for 2008
 

Off subject a little--Is there a csv with all the teams and their addresses that I can get my hands on. I would love for my Geospatial Tech class to use the opr data and do some geocoding to look at trends.

Re: Offensive Power Rankings for 2008
 

Can someone post CT?

Re: Offensive Power Rankings for 2008
 

I would like to see VCU