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Thousandths, Rounding, and Score History (Nit-Picking)


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I realize this topic is kind of picky, but...

Under the new scoring system, the smallest increment of difference between two corps is 0.0125, or 1/80th of one point. DCI Southeast saw Blue Devils beat Vanguard by this margin.

Scores are being reported to 3 decimal places, even when the "real score" goes to 4.

When announced over the loudspeaker, DCI seems to consistently prefer the "round half up" algorithm we learned in elementary school: if the ten-thousandths digit is a 5, round up to the nearest thousandth. As a result, all scores this season as announced have only specified 0, 3, 5, or 8 as the final digit. So

  • 97.0125 would be announced as 97.013
  • 97.3625 would be announced as 97.363, and
  • 98.0375 would be announced as 98.038

But I've noticed that competitionsuite.com, DCI's choice for hosting scores and recaps, is using a different algorithm. I can't quite tell what that algorithm is. I thought it was "banker's round" (definition) but I can find counter-examples.

For Prelims on DCI.org there is:

  • Blue Devils with 97.362 (announced as 97.363)
  • Carolina Crown with 96.363
  • Bluecoats with 94.638
  • Cadets with 92.263
  • Mandarins with 84.213
  • Pacific Crest with 77.787 (announced as 77.788)
  • Jersey Surf with 71.613
  • Louisiana Stars with 71.563
  • The Company with 70.037 (announced as 70.038)
  • Southwind with 68.838
  • Guardians with 67.838
  • Pioneer with 65.913

My best guess was that the rounding depends on the "one's digit": if the last digit before the decimal point is odd, round down; if it's even, round up. But if that were true, Surf's score should be showing as 71.612, The Company as 70.038, Guardians as 67.837, and Pioneer as 65.912.

I realize that this is a tiny detail that can never affect the placement of the corps, but it does affect "the record books" like CorpsReps and FromThePressbox.

Does anyone know for certain:

  • What rounding algorithm Competition Suite is using?
  • As far as "official" scores, is DCI's official position to "always round up" (so xx.xx75 always is xx.xx8 and xx.xx25 always is xx.xx3) or whatever Competition Suite is doing?
Edited by JimBurnell
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Contact Matt Becker at CompetitionSuite.  matt@competitionsuite.com

Really [anything]@competitionsuite.com goes to Matt.  He owns the domain.  

Anyhow, he's a good guy and would be able to reconcile the question.  He'd also be interested if the system were somehow yielding varied results in different media (judge app vs. user app vs. AWS host vs. pdf).

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6 minutes ago, HbRJgdZHsbc said:

Contact Matt Becker at CompetitionSuite.  matt@competitionsuite.com

Really [anything]@competitionsuite.com goes to Matt.  He owns the domain.  

Anyhow, he's a good guy and would be able to reconcile the question.  He'd also be interested if the system were somehow yielding varied results in different media (judge app vs. user app vs. AWS host vs. pdf).

Thanks! I've sent him an email.

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my hunch is it's how DCI wants to round it up when they announce

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59 minutes ago, Jeff Ream said:

my hunch is it's how DCI wants to round it up when they announce

Should have checked, but given that the recaps are rounding up, I agree. It must be a bug in the software that displays the totaled scores.

Matt's reply:

Hey Jim,
I'll definitely take a look at this. I know years ago, there was an issue in the software (where the Announcer sheet is printed) that was using Bankers rounding (it's the default rounding method in .NET). I thought we were careful with all other avenues when we do rounding, but we may have missed something.

I'll get back to you as soon as I have more information.

-Matt

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33 minutes ago, JimBurnell said:

Should have checked, but given that the recaps are rounding up, I agree. It must be a bug in the software that displays the totaled scores.

Matt's reply:

Hey Jim,
I'll definitely take a look at this. I know years ago, there was an issue in the software (where the Announcer sheet is printed) that was using Bankers rounding (it's the default rounding method in .NET). I thought we were careful with all other avenues when we do rounding, but we may have missed something.

I'll get back to you as soon as I have more information.

-Matt

Matt is the best!  He loves data and information.

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Got a VERY early morning (2:58am) reply from Matt.

It appears that we may be going to 4-decimal scores! I checked this morning and recaps are showing 4 decimal places now.

Here's his reply:

Hi Jim,
I've released an updated recap that has the full scores (out to 4 digits). The DCI site is still showing scores to 3 digits instead of 4. This requires a change on their side and I'll be discussing the change with them shortly.

Thank you very much for bringing this to my attention. If you notice anything else, please don't hesitate to send me a message.

-Matt

Edited by JimBurnell
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2 hours ago, JimBurnell said:

Got a VERY early morning (2:58am) reply from Matt.

It appears that we may be going to 4-decimal scores! I checked this morning and recaps are showing 4 decimal places now.

Here's his reply:

Hi Jim,
I've released an updated recap that has the full scores (out to 4 digits). The DCI site is still showing scores to 3 digits instead of 4. This requires a change on their side and I'll be discussing the change with them shortly.

Thank you very much for bringing this to my attention. If you notice anything else, please don't hesitate to send me a message.

-Matt

...and now they're back to 3 digits, but the summary pages on DCI's site finally follow the same rounding algorithm (round up, so scores never end in a 2 or 7, only in a 0, 5, 5 or 8).

Edited by JimBurnell
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Final response:

The only recap that had been updated was Finals. All recaps this season have been updated now.

The "final decision" is 3 decimal places, standard rounding (0-4 round down, 5-9 round up) until they are able to update their site to allow for 4 decimals (to match the recap). They did qualify the decision with a "we may change our mind" comment.

-Matt

 

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