Pricing logic oddity

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Pricing logic oddity

Postby texasaggie » Tue Jul 31, 2012 7:47 pm

I think I figured out another issue with pricing. I think it is a bug but I could see how some folks may argue it is just a happenstance. After updating, I had some ridiculously high prices on some commons ($25.00 vs $0.10). I did some looking at the source price guide (magictraders) and noticed what I describe below. I did more digging after annotating the screenshot though and found the problem.

The logic that Gad is using when there are multiple editions of cards seems to be if there is a price in the guide that is not attributed to an edition and others that are, that price is averaged in with the edition specific price to come up with the other price. For example, with Flood below, there is a $.28 price for 4E, a $.40 price for DK and a 50.00 price with no edition in the price guide. The 5E flood in my collection was tagged with the $50.00 price (which I don't like but understand). It took me a minute to track down the $25.14 price for the 4E, since I could see $.28 in the price guide. After some other digging, I was able to determine that $25.14 was averaged from $50 and $.28. Similarly, the Dark version was showing as $25.20, which is the average of $50 and $.40. The Battle Royale edition shows $50.

My argument here is that if there are edition specific prices (and multiple editions), that any unattributed price (not tied to an edition) should not be averaged in with an attributed (to an edition) price. In my case, that would have fixed the 4E and DK errors above, but left the Battle Royale and 5E problem. This isn't perfect but it is only as good as the pricing data.

Normally its not that big of a deal, but I have a *lot* of these type issues and this one card alone resulted in an "overinflation" of $800.00. I still contend we would be better off with an ability to "correct" these outrageous prices in the market price column but that's a different subject. For now, I'd be interested to see what others think about this.

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Re: Pricing logic oddity

Postby gaddlord » Wed Aug 01, 2012 9:44 am

And here is exactly why: MTG Studio does add the $50 price to all reprints of the card.

This way the 4ED Flood has both $50 and $0.28 and the average becomes $25.

Here is the solution:
1. I will extend the Prices to have Edition as well.
2. Make sure that I try to fetch the same edition price first. And if this fails then to take the average of all editions. This way the average would be more accurate.
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Re: Pricing logic oddity

Postby texasaggie » Wed Aug 01, 2012 10:52 am

gaddlord wrote:1. I will extend the Prices to have Edition as well.
2. Make sure that I try to fetch the same edition price first. And if this fails then to take the average of all editions. This way the average would be more accurate.


I think this change will make it more reasonable most of the time. I know it won't fix all the problems, but I think it will be closer to reality in many cases. Let me know if you want me to help beta test it. Thanks gadd!
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Re: Pricing logic oddity

Postby gaddlord » Tue Sep 04, 2012 7:23 am

Fixed in 3.1.
Beta version available for download from https://dl.dropbox.com/u/3607590/mtgstudio/mtgstudio.exe.
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Re: Pricing logic oddity

Postby texasaggie » Tue Sep 04, 2012 7:03 pm

gaddlord wrote:Fixed in 3.1.
Beta version available for download from https://dl.dropbox.com/u/3607590/mtgstudio/mtgstudio.exe.


Gadd- downloaded and tried it and got an error immediately when importing prices from magictraders. I sent the bug report. Do I need to download any other supporting files (or delete the existing pricing temporary file/db)?
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Re: Pricing logic oddity

Postby texasaggie » Wed Sep 05, 2012 7:33 am

Never mind on the error. I deleted/renamed mtgstudio.prices in my user data directory. I figured the new schema caused the issue. It is importing prices now and I'll try the update and let you know.

Thanks!
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Re: Pricing logic oddity

Postby texasaggie » Wed Sep 05, 2012 8:20 am

The pricing logic change seems to work. I checked against the one I reported in the thread (Flood) and the logic for the specific editions is pulling only from those. The remaining cards of the same name are averaged still, but this is much closer to reality in a lot of cases.

Longer term, Gadd how would you feel about allowing us to specify a local file with prices in it instead of only magic traders? If I could download a magic traders file and either remove the serious outliers (like the $50 flood entry) or correct it back down to something reasonable and then import into the existing pricing update, would that work for you? I think that would strike a good balance between your concerns about editing the market price data directly in the tool and the need to try and get down more reasonably in prices. Arguably this is typically only an issue with older cards but it does swing the prices wildly.

Thanks Gadd!

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Re: Pricing logic oddity

Postby gaddlord » Wed Sep 05, 2012 3:43 pm

How would you feel about allowing us to specify a local file with prices in it instead of only magic traders?

Maybe the solution to this can be

1. allow exporting the existing mtgstudio.prices Price Lists to CSV with Edition Name, Card Name, Price, Quantity, Price List source, Condition, Foil
2. you can use any CSV editor (such as Excel or even notepad) to amend the values
3. allow importing the CSV prices back in mtgstudio.prices Price Lists file
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Re: Pricing logic oddity

Postby texasaggie » Wed Sep 05, 2012 3:56 pm

gaddlord wrote:
How would you feel about allowing us to specify a local file with prices in it instead of only magic traders?

Maybe the solution to this can be

1. allow exporting the existing mtgstudio.prices Price Lists to CSV with Edition Name, Card Name, Price, Quantity, Price List source, Condition, Foil
2. you can use any CSV editor (such as Excel or even notepad) to amend the values
3. allow importing the CSV prices back in mtgstudio.prices Price Lists file


That sounds great. I thought it would be easier not as CSV but that depends on what you have built already to leverage.
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Re: Pricing logic oddity

Postby oldmanmagic » Tue Oct 02, 2012 10:15 pm

I wonder if there would be a way to drop the highest or lowest x prices for an item or come up with a mathematical format that would maybe look at the average of all the prices as compare it to the highest price found and lowest price found and make a decision on if it should be included or not.
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Re: Pricing logic oddity

Postby texasaggie » Wed Oct 03, 2012 6:00 pm

oldmanmagic wrote:I wonder if there would be a way to drop the highest or lowest x prices for an item or come up with a mathematical format that would maybe look at the average of all the prices as compare it to the highest price found and lowest price found and make a decision on if it should be included or not.


I presume that is what the sites do that are pricing sources is run some sort of average. The issue seems to be cards that are not attributed to particular sets that in some cases have ridiculously high prices (e.g. Flood a common for $50.00).
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Re: Pricing logic oddity

Postby gaddlord » Fri Oct 19, 2012 5:13 am

We use 2 ways to do average:

1. When you add a card to the collection from Add To Collection menu. Or whenperforming Update Prices we use:
Avg. for the same card version of the card from the same set with the same foilness.

2. When using the Buy At, Sell At "..." popup window we use Smart Average which a more accurate fair price caluclated this way:
http://mtgstudio.com/wiki/index.php?title=Smart_Average

Name Edition Market Price
Flood BR 16.89
Flood 5E 16.89
Flood 4E 0.28
Flood DK 0.4

I see them with quite lower values for 4E and DK. Can you send over your mtgstudio.prices file to gaddlord@mtgstudio.com and mention in the subject "Pricing logic oddity", pls.
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