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My Bimonthly Review of the Values of My Collection
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108 posts in this topic

1950's war comics

1950's war comics

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@Math Teacher i once went to watch a professional senior bowling tournament and there was some big stars there , but one of the guys i had never heard of was pretty good too and i found out that he was in his fifties and had been avidly bowling for 45 years and that he had written down by hand every single game he had bowled in his whole life,  frame by frame, and that he had saved every one of them in a five drawer file cabinet ,

his day job career was as a statistician ...

just another example for you of how the mind of a mathematician can work

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Math Teacher

Math Teacher

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4 hours ago, 1950's war comics said:

@Math Teacher i once went to watch a professional senior bowling tournament and there was some big stars there , but one of the guys i had never heard of was pretty good too and i found out that he was in his fifties and had been avidly bowling for 45 years and that he had written down by hand every single game he had bowled in his whole life,  frame by frame, and that he had saved every one of them in a five drawer file cabinet ,

his day job career was as a statistician ...

just another example for you of how the mind of a mathematician can work

I suppose you could say that what I am doing falls into that same type of OCD, although not to the Nth degree as the bowler mentioned. I am glad that I have the level of OCD that I do - it helps me keep things organized, but it's not crippling. I would be willing to bet that the majority of successful people (Bill Gates, Steve Jobs, Warren Buffet, etc.) all had varying levels of OCD in their life.

But, just for a counterpoint, my wife is very right-brained, just as I am very left brained. My wife has virtually no sense of math, but she is very creative; she knits, she cross stitches, she makes quilts, and she creates for our grandson (making a gingerbread house was yesterday's project). And she also likes to put together puzzles. On every puzzle she works on, she keeps a detailed list of how many she finds in a given session. I think she keeps this information for each puzzle she does.So she  sounds something like the bowler you mentioned above, although her career is not even remotely related to statistics.

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Math Teacher

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9 hours ago, bpc3qh said:

Perhaps, although the timing of your data would seem to still include the period in which the book was hot? (Although it's also possible I'm misremembering when the book was hot.) Either way, I expect the book to increase again in 2021, especially as we get closer to Ant-Man 3's trailers and such, probably in the second half of the year.

Well, there were only two sales of AV #8 CGC 7.0 in the time frame of October 31, 2020, to December 31, 2020. The first sale was $1,200 on November 26 and the second sale was $1,055 on December 27. $1,055 was the data point that I used for the value on December 31. The last sale in the August 31, 2020, to October 31, 2020 time frame was $1,225 on October 28. If you subtract the current value,$1,055, from the previous value, $1,225, you get a loss of –$170. If you divide this loss (–$170) by its previous value ($1,225), you get a –13.9% decrease from my recorded values of $1,225 and $1,055. This is exactly what I have on my spreadsheet.

For GoCollect, I can't provide the dates of sales like I can for GPA. I'm not a full-fledged member of GC. At the end of October, the current value of AV #8 CGC 7.0 was $1,200, while the current value of the same book was $875 at the end of the December. ($875 – $1200) / $1200 gives a –27.1% decrease, as I listed above. It would be safe to say that the price of $875 is an outlier, which I don't take into account.

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bpc3qh

bpc3qh

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34 minutes ago, Math Teacher said:

Well, there were only two sales of AV #8 CGC 7.0 in the time frame of October 31, 2020, to December 31, 2020. The first sale was $1,200 on November 26 and the second sale was $1,055 on December 27. $1,055 was the data point that I used for the value on December 31. The last sale in the August 31, 2020, to October 31, 2020 time frame was $1,225 on October 28. If you subtract the current value,$1,055, from the previous value, $1,225, you get a loss of –$170. If you divide this loss (–$170) by its previous value ($1,225), you get a –13.9% decrease from my recorded values of $1,225 and $1,055. This is exactly what I have on my spreadsheet.

For GoCollect, I can't provide the dates of sales like I can for GPA. I'm not a full-fledged member of GC. At the end of October, the current value of AV #8 CGC 7.0 was $1,200, while the current value of the same book was $875 at the end of the December. ($875 – $1200) / $1200 gives a –27.1% decrease, as I listed above. It would be safe to say that the price of $875 is an outlier, which I don't take into account.

Interesting--I suppose my mental picture of where the book is at doesn't match reality. This thread taught me something!

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piper

piper

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When you have a book with little sales data, I think it’s important to take a holistic view of the data. For example, what’s happening with other grades?

My sense is that Avengers 8 is scorching hot.

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Math Teacher

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27 minutes ago, piper said:

When you have a book with little sales data, I think it’s important to take a holistic view of the data. For example, what’s happening with other grades?

My sense is that Avengers 8 is scorching hot.

That may very well be true. But I am working only with the books that are in my collection. Avengers #8 in other grades than 7.0 are out of my purview.

Now, it might be an interesting project for someone else. But I have already put enough time and effort in my original post and thoughts. I'll leave it to someone else.

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valiantman

valiantman

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12 hours ago, Callaway29 said:

@valiantman would love this convo, and probably have some insightful contributions.

Contributions?  Yes.  Insightful?  Maybe. lol

I just reviewed the conversation fairly quickly - my first question would be "Which GPA price?"  - yes, I know it's GPAnalysis.com but there is "last sale price", "90 day average", "12 month average".  My impression from GoCollect (which I don't use) is that they're probably closer to a 90-day, 6-month, or 12-month average which makes them seem "slower", but if you use the same timeframe (you could calculate 6-month GPA average by hand, if that's what GC uses) from both sites - I would guess the GC-to-GPA prices would be very correlated on the same timeframe.  By the way, @Math Teacher the Excel correlation of two columns of prices (Column A, Column B, 50 rows) would be =CORREL(A1:A50,B1:50)

Looking at the GoCollect website, they don't actually say which sale prices they're using (and GC does mention using humans (shrug) :grin:) , so GPA is always more accurate when you include the timeframe with the dollar amount.  "The 90-day GPA average is $X, with Y sales" is an accurate statement.  "GoCollect says the value is $X" doesn't tell you much that is useful from a "Math Teacher" standpoint - since we don't know how many sales are being used, how much time was used, or whether some sales are weighted differently based on venue or time-since-the-sale.  Variables that matter, if we're doing math like this conversation.  The details don't matter much if we're just quoting GC prices. lol

Some books sell constantly (ASM #300) while others might only sell twice a year (particularly in a given grade)... so the month-to-month comparison is harder because "no price change" can mean A) no sales of that book in any grade, B) no sales at that grade but other grades went up, C) no sales at that grade but other grades went down, D) multiple sales at that grade but the price didn't change.  Similarly, an increase in price in GPA implies there are recent sales, but for any given grade, the increase could be disproportionate vs. other grades, and it's not uncommon for mid-grades (which vary by comic) to have a sale at $300 for 8.5 and $320 for 8.0 (maybe even on the same day), so who knows what the "correct math" would do with either grade's value.

Overall, though, @Math Teacher is to be congratulated for actually getting into the data - because there's a whole lot of talk in this hobby "around the data" but not as much "in the data".  The tagline for my website (slabdata.com) is "Nerds like slabs, bigger nerds like slab data" and it's always great to hear from bigger nerds because regular nerds tend to exaggerate in their own favor quite a bit. :kidaround:

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Math Teacher

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25 minutes ago, valiantman said:

I just reviewed the conversation fairly quickly - my first question would be "Which GPA price?"  - yes, I know it's GPAnalysis.com but there is "last sale price", "90 day average", "12 month average". 

In my methodology, I always use the last sale price. Is that the right way to go? Who knows? And the other problem with the last sale price may have occurred in January, 2020, or perhaps even before. For example, the last sale price for Amazing Adventures #1 CGC 3.0, $220, occurred in December, 2019. That price doesn't have a great deal of validity for today's price of AA #1 3.0, but it's all I have to go on. Let's be honest - Amazing Adventures #1 doesn't come up for sale that often.

CGC 8.0 - $1,690 - August, 2020
CGC 7.5 - $1,075 - July, 2020
CGC 7.0 - $504 - February, 2020
CGC 7.0 - $492 - July, 2020
CGC 6.5 - $792 - November, 2020
CGC 5.5 - $408 - July, 2020
CGC 5.5 - $474 - December, 2020
CGC 4.5 - $439 - May, 2020
CGC 2.0 - $250 - September, 2020
CGC 0.5 - $91 - December, 2020 (Incomplete)

So, by my count, I see ten sales of the book in any grade during 2020, based on GPA's data. But, the last time a CGC 3.5 was sold was in Jun, 2011. Books that rarely change hands can definitely skew the data, but I'm not sure to what degree.

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valiantman

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1 hour ago, Math Teacher said:

In my methodology, I always use the last sale price. Is that the right way to go? Who knows? And the other problem with the last sale price may have occurred in January, 2020, or perhaps even before. For example, the last sale price for Amazing Adventures #1 CGC 3.0, $220, occurred in December, 2019. That price doesn't have a great deal of validity for today's price of AA #1 3.0, but it's all I have to go on. Let's be honest - Amazing Adventures #1 doesn't come up for sale that often.

CGC 8.0 - $1,690 - August, 2020
CGC 7.5 - $1,075 - July, 2020
CGC 7.0 - $504 - February, 2020
CGC 7.0 - $492 - July, 2020
CGC 6.5 - $792 - November, 2020
CGC 5.5 - $408 - July, 2020
CGC 5.5 - $474 - December, 2020
CGC 4.5 - $439 - May, 2020
CGC 2.0 - $250 - September, 2020
CGC 0.5 - $91 - December, 2020 (Incomplete)

So, by my count, I see ten sales of the book in any grade during 2020, based on GPA's data. But, the last time a CGC 3.5 was sold was in Jun, 2011. Books that rarely change hands can definitely skew the data, but I'm not sure to what degree.

One method, which is valid for most Silver Age books in the mid-to-low grades (let's say 6.0 down to 2.0) is to use "price per point" when there are very few sales.

So, in the case of Amazing Adventures #1 CGC 3.0, there was a sale in September 2020 of 2.0 for $250, or $125 per point.

The sale of CGC 5.5 in December 2020 was $474, which is $86 per point.

Using that range of "recent prices" it would probably be fair to estimate CGC 3.0 as $258 to $375 (which is $86 to $125 per point).  The lower end estimate ($258) is also the most recent, being $86 per point from a December mid-grade sale.

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jhm

jhm

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Oh boy... it seems like there may be some misunderstandings about the information on GoCollect. If you're not paying a monthly subscription to GoCollect, you're not getting anywhere near the amount of information you could be.

Email help@gocollect.com and tell them Jeff said he was willing to give anyone that doesn't have a membership a free 30 days to try it. Feel free to point back to this thread. And if they give you any grief at all... just tell me and I'll have each and every one of them strung up by their toe nails!!!! But seriously... the folks that handle support are awesome and are always willing to give you a look behind the curtain if you reach out to them :fear:

@Math Teacher and @valiantman you would probably both enjoy our valuation modeling tools. Here's the one for the ASM #300 for instance: https://comics.gocollect.com/guide/comicValueModels/gcin/150744 Click the "About" button to get a sense of how these work, how you can generate multiple for any comic, and how you can share your models with other account holders.

I would encourage everyone to read my comments from similar posts in the past. My most recent one was written when I was feeling super grumpy, but I laid out some things pretty straight there:

 

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Mr bla bla

Mr bla bla

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On 1/2/2021 at 10:36 AM, 1950's war comics said:

@Math Teacher i once went to watch a professional senior bowling tournament and there was some big stars there , but one of the guys i had never heard of was pretty good too and i found out that he was in his fifties and had been avidly bowling for 45 years and that he had written down by hand every single game he had bowled in his whole life,  frame by frame, and that he had saved every one of them in a five drawer file cabinet ,

his day job career was as a statistician ...

just another example for you of how the mind of a mathematician can work

Pretty autistic. Reminds me of myself 👍

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Mr bla bla

Mr bla bla

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2 hours ago, Math Teacher said:

Some people's obsession of slips of papers usually labels them as a hoarder or autistic.  However, if you get audited by the IRS, you'll be thankful that you have these slips of paper.

Definitely ...👍

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