Author Topic: Weavers DRI Calculation Suggested Improvement  (Read 7057 times)

Ed and Tres

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Re: Weavers DRI Calculation Suggested Improvement
« Reply #15 on: April 07, 2019, 06:14:13 PM »

Looking at all DRI's number for Weavers it looks like this:
Under 125 yards: 5.54% got over 100
Between 126 and 150 yards: 8.1% got over 100
Over 150 yards: 11.12% got over 100 DRI.

Now what is interesting there, is that DRI's were originally reserved for the top 5% of dogs in a class.

We lightened it up and made it the top 10%.

So then we're getting into a question of whether we are just continuing to lessen the standards to meet what people want.  Versus what the original goal was actually meant to be.

Based on this and the post after this one where it shows for Tunnelers all lengths are closer to 10%, I would have to conclude that it is harder to get a 100+ DRI on a shorter Weavers course.

I am not advocating a change just acknowledging what Chris' great statistics show.

Thanks for sharing the data Chris, this is definitely an interesting topic that Arne brought up.

As to how to compare your times within different Weaver length courses, my math skills are not that good but if under 150 then your DRI would likely be higher on a longer course if your dog ran at it's normal speed thru course.

The DRI is an interesting number but every run / trial has variables and you just need to consider that when analyzing numbers.

Perhaps you dog is faster at inside trial, maybe faster on overcast days at outside trials. 
Ed & Tres
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Morristown, NJ

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Re: Weavers DRI Calculation Suggested Improvement
« Reply #16 on: April 07, 2019, 09:35:26 PM »
Great discussion!  I do apologize in that I was not thinking about all the awards NADAC has tied to DRI in my original post.  I can see how any change in the calculation could ruffle some feathers.  My current dog is fast but he is not a regular member of the 100+ DRI club.  It makes no personal difference to me whether the 100 DRI is based off of the top 5% or off of the top 10%. What does make the DRI such a powerful tool is that it is based off of the fastest runs.  Chances are that the vast majority of the 100+ DRI runs did not have any off courses or bobbles or missed weave entrances.  It gives me a clear marker of what the best teams can accomplish. It is something I cannot get with only data from my dog - with lots of off courses and bobbles and missed entrances.  My goal for the post was only to improve the tool for Weavers where I thought distance had a strong influence on the current DRI calculation and really diminished its power.  I agree with Ed that the numbers Chris posted seem to support the influence of distance on the Weavers DRI.

As Chris stated, the easiest way to fix the problem would be make all of the Weavers courses the same length. My guess would be if the courses were all within a range of 25 yards, the distance influence on the Weavers DRI would probably be +/-2 or 3 from the average.  Or to state differently, the same run on the shortest allowed course might have a DRI of about 5 less that of the longest allowed course.  But that is only an estimate based on my proposed formula that uses the Tunnelers DRI 100.  As others posted, that might not be the perfect DRI 100 to use because there could also be Hoops.

I was amazed at how fast Chris came back with the various statistics from the DRI calculations.  All the data must already be in easily manipulated spreadsheet form?  If that is true, there would be no need to use a formula like I originally posted.  The rest of this post is just a proposed alternative way to calculate a Weavers DRI without a distance influence if that is the decided path.  This alternative DRI would also help get the desired percentage of dogs with a 100 DRI+ regardless of course length.  If you like the math, continue reading.  If not, don't worry about the rest of this post.

If you have all the yps data with the length of each associated run, I would make two Excel columns - one for yps and the second for the associated run length.  I would sort the data together on run length. Depending on how much data I had, I would break the data up into set run length increments (maybe 100-105, 106-110, 111-115, etc).  I would then sort each of those increments on yps.  I would take the top percentage ("top" being whatever I wanted the DRI 100 based on) and average for the DRI 100 for each increment.  I would then do a best fit with DRI 100 on the y-axis and run length on the x-axis.  (If a good best fit is a horizontal straight line, then you have proved there is no distance impact on DRI. I highly doubt that will be the case. You might need a second order fit.)  All this work is a one time (or maybe every few years) deal.  Once you have the equation of the line, you just put it in another excel speadsheet.  Then for each course you could just enter the course length into the equation and it will calculate the adjusted DRI 100 for that course.



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Re: Weavers DRI Calculation Suggested Improvement
« Reply #17 on: April 08, 2019, 07:21:09 AM »
If you are not comfortable with finding the equation of a best fit curve, you could get similar results with a long IF statement plugging in the calculated DRI 100 for each increment of course length. 

Re: Weavers DRI Calculation Suggested Improvement
« Reply #18 on: April 08, 2019, 09:08:43 AM »
I have to think about this a bit more before we say too much.

But just some numbers to play with:

Out of 565 Weavers runs with a 100+ DRI

14% were under 125 yards
48% were between 126 and 150 yards
36% were over 150 yards

Compare that to Tunnelers where we have a little more data with 1094 runs over 100 DRI:

14% were under 125 yards
48% were between 126 and 150 yards
36% were over 150 yard

Since those numbers are exactly the same I went ahead and did Jumpers too which is:

528 runs

1.3% were under 125 yards
88% were between 126 and 150 yards
9.84% were over 150 yards.

Everyone can deduce what they want from those numbers.   

While I think that the numbers are interesting, I think what Arne was trying to say is that in weavers, a shorter weavers course is made up of a lot more ground on weaves, which for any dog, is slower than simply running through a tunnel.  I get where he is coming from as a tool to look at my progress.  I use them for the same reason.  Whoever wrote that we could all do our own, yeah that is awesome if I had all the time in the world.  I don't and I run 4 dogs, so the amount of data entry after each trial would be a lot since I generally run 40 events in a typical weekend.  The DRI is a nice, easy way to compare from time to time.  In fact, I just did a graph (because I am a numbers geek and because the numbers were readily available) on one of my dogs to compare all of her DRI's over the past 8 years to see how she is holding up as she turned 12 today.  Her DRI's have actually stayed pretty consistent on the events I did, so it was interesting to see.   Maybe instead of adjusting the DRI, YPS could be on the download?
Audri, Lily, Cee Cee and Toto, Calypso