Quote:
Originally Posted by mitchellzone
I do have a question on how you've calculated these numbers, though. I'm assuming for a given event you're taking averages, but how do we end up with negative numbers for things like teleop high boulder points, etc.? There are several fields with values like this that I don't understand as the minimum value should really be zero.
Can you explain this? Thanks.
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These numbers are calculated using a least-squares approximation on qualification scores assuming that every team contributes the same amount to the selected category in every match. This value is each team's calculated contribution (or OPR) in that category. The only inputs to the algorithm are the category scoring breakdown per match and the match schedule. For more detail on how OPR is calculated, see the first link on
this page titled "Presentation to explain new scouting database."
As to why negative values arise, there are two main reasons this could occur. First, recognize that these values represent a given team's
contribution to a given category, which is generally not equivalent to what we conventionally think of as scoring. For example, a team which never takes shots, but transports boulders into the courtyard, could have a positive value in "teleop Boulders High." Although scouts would never say that they scored boulders high, if alliances which they are a part of tend to score more high goals, their "teleop Boulders High" value might be positive. In the same way, if a team plays the game in a way that hinders partners from scoring high boulders (by taking balls from them, taking their desired shooting position, running into them, etc...) then this team will have a justifiably lower score in "teleop Boulders High" than just the average number of boulders they themselves scored high.
The other reason a team could have a negative value in a category boils down to our assumption that every team contributes the same amount every match. This is very clearly false, but it is a reasonable enough approximation that we can still arrive at reasonably good results when making it. If team A never scores in the high goal, but happens to be on the same alliance as a very good shooter in the same match that the shooter breaks down, team A will likely receive a small negative value in "teleop Boulders High."
Personally, when I interpret these values, I generally round all negative values up to 0, but YMMV.
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Also, I'm wondering if you'll be producing a sheet that contains only the teams going to Worlds in St. Louis? That would be helpful for those who are going.
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Good idea. I will include a sheet like this in my next update.
Quote:
Originally Posted by mitchellzone
Thought of another couple:
Does this data just reflect qualification rounds or also playoff rounds? I assume the latter, but wanted to verify.
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I do only factor in qualification rounds. There are a number of reasons for this, many of which are described by Ed Law
here. The reasons there are important, but the largest reason for me is that using qualification matches only has become the de facto standard on calculations like these, and it is important to me that my scores are equivalent to those listed on TBA, the 2834 database, and the 1114 database.
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Also, how are you calculating total points? This seems to be a really low number...
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Total points is actually equivalent to OPR. This number represents the calculated contribution to the match scores of a team throughout their qualification matches.
Remember that these numbers represent only the given teams' contribution, not their average alliance's score. Also, remember that playoff scores are calculated differently than qual scores. If you want to approximate a playoff alliance's score, you will likely get better results using my eOPR1 or eOPR2 metrics.
Crazy is relative - dtengineering [more] 
17-04-2016, 13:51
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