My Bimonthly Review of the Values of My Collection 8 8

[Math Teacher]

Well, here I am with my bimonthly report on the value of my collection. This is a LONG article, so you may want to go get a snack before you start reading.

 

So, according to GoCollect, the value of my collection increased 3.1% from the end of October to the end of December. According to GPAnalysis, for the same time period, the value of my collection increased 6.8%. In general, GPAnalysis usually shows a larger increase than GoCollect.

 

December, 2018, to February, 2019: GoCollect 4.0%, GPAnalysis 5.6%
February, 2019, to April, 2019: GoCollect 22.7%, GPAnalysis 20.2%

April, 2019, to June, 2019: GoCollect 14.6%, GPAnalysis 16.0%

June, 2019, to August, 2019: GoCollect 17.2%, GPAnalysis 14.4%

August, 2019, to October, 2019: GoCollect 5.6%, GPAnalysis 0.0%

October, 2019, to December, 2019: GoCollect 8.2%, GPAnalysis 5.8%

December, 2019, to February, 2020: GoCollect 8.6%, GPAnalysis 12.6%
February, 2020, to April, 2020: GoCollect 4.2%, GPAnalysis 4.4%
April, 2020, to June, 2020: GoCollect 13.0%, GPAnalysis 10.6%

June, 2020, to August, 2020: GoCollect 5.1%, GPAnalysis 9.5%

August, 2020, to October, 2020: GoCollect 7.9%, GPAnalysis 8.8%

October, 2020, to December, 2020: GoCollect 3.1%, GPAnalysis 6.8%

 

Just so you know, I didn’t take the time to remove new books I had acquired over each two month period.

 

According to GoCollect, the following books showed a 15% (or higher) increase or decrease in value from October 31 to December 31:

 

Amazing Adventures #1 CGC 3.0: 16.1% increase

Avengers #3 CGC 6.5: 22.7% increase

Daredevil #7 CGC 6.5: 26.7% increase

Avengers #8 CGC 7.0: –27.1% decrease

Avengers #14 CGC 8.5: –16.7% decrease

Black Knight #1 CGC 4.5: –41.5% decrease

Brave and the Bold #62 CGC 9.0: 15.4% increase

Daredevil #7 CGC 6.5: 26.7% increase
Fantastic Four #1 CGC 2.5: –18.9% decrease

Fantastic Four #5 CGC 2.5: 51.7% increase
Fantastic Four #52 CGC 6.5: –16.0% decrease

Flash #123 CGC 4.5: 20.8% increase
Flash #137 CGC 8.0: 33.3% increase
Green Lantern #1 CGC 4.0: 23.3% increase
Journey Into Mystery #114 CGC 7.5: –17.9% decrease

Justice League of America #1 CGC 4.0: 20.8% increase

Rawhide Kid #17 CGC 3.5: –27.3% decrease

Showcase #22 CGC 4.5: 25.8% increase
Showcase #27 CGC 7.0: –17.1% decrease

X-Men #1 CGC 3.0: 19.8% increase
X-Men #3 CGC 6.5: 45.8% increase

 

According to GPAnalysis, the following books showed a 15% (or higher) increase or decrease in value from October 31 to December 31:

 

Amazing Spider-Man #4 CGC 3.5: 22.4% increase
Amazing Spider-Man #5 CGC 4.0: 28.6% increase
Amazing Spider-Man #6 CGC 5.5: 16.3% increase

Amazing Spider-Man #9 CGC 5.5: 39.0% increase

Amazing Spider-Man #11 CGC 6.0: –21.3% decrease

Amazing Spider-Man #13 CGC 4.0: 23.1% increase
Amazing Spider-Man #101 CGC 6.5: 212.5% increase

This was due to an outlier of $200 price for this book on October 24, 2020

Avengers #1 CGC 1.5: –18.5% decrease
Avengers #4 CGC 2.5: 22.9% increase

Avengers #5 CGC 6.5: 19.5% increase

Avengers #6 CGC 6.0: 21.5% increase

Avengers #14 CGC 8.5: 58.6% increase
Avengers #16 CGC 7.0: 48.6% increase

Black Knight #1 CGC 4.5: –30.6% decrease

Brave and the Bold #29 CGC 4.0: 16.4% increase

Daredevil #7 CGC 6.5: –24.9% decrease

Fantastic Four #1 CGC 2.5: 20.1% increase

Fantastic Four #6 CGC 3.5 (C-1): 56.3% increase

Fantastic Four #13 CGC 7.5: 24.9% increase

Fantastic Four #52 CGC 6.5: 21.4% increase

Flash #123 CGC 4.5: 34.1% increase

Incredible Hulk #1 CGC 1.5: 59.0% increase

Incredible Hulk #181 CGC 8.5: 16.8% increase

Journey Into Mystery #85 CGC 4.5: 45.0% increase
Journey Into Mystery #114 CGC 7.5: –22.9% decrease

Justice League of America #1 CGC 4.0: 45.1% increase

Sgt. Fury and His Howling Commandos #1 CGC 4.5: 19.7% increase

Showcase #17 CGC 3.5: 34.6% increase
Strange Tales #101 CGC 6.0: 44.0% increase

Strange Tales #110 CGC 3.0: 24.7% increase
Tales of Suspense #50 CGC 5.5: 17.3% increase

Tales of Suspense #57 CGC 5.5: 20.0% increase
Tales to Astonish #57 CGC 7.5: –46.2% decrease

Wolverine #1 Chirstopher Variant CGC 9.8: –19.8% decrease
X-Men #14 CGC 7.0: –16.3% decrease

 

I think it is interesting when you compare these two companies together. Here are some examples:

 

Amazing Spider-Man #4 CGC 3.5: GC 0.0% increase, GPA 22.4% increase

Amazing Spider-Man #9 CGC 5.5: GC  5.0% increase, GPA 39.0% increase

Avengers #4 CGC 2.5: GC –3.6% decrease, GPA 22.9% increase

Avengers #6 CGC 6.0: GC 0.0% increase, GPA 21.5% increase

Avengers #14 CGC 8.5: GC –16.7% decrease, GPA 58.6% increase
Avengers #16 CGC 7.0: GC 11.1% increase, GPA 48.6% increase
Brave and the Bold #29 CGC 4.0: GC –7.4% decrease, GPA 16.4% increase

Daredevil #7 CGC 6.5: GC 26.7% increase, GPA – 24.9% decrease 

Fantastic Four #1 CGC 2.5: GC –18.9% decrease, GPA 20.1% increase

Fantastic Four #5 CGC 2.5: GC 51.7% increase, GPA 0.0% increase

Fantastic Four #6 CGC 3.5 (C-1): GC –0.8% decrease, GPA 56.3% increase

Fantastic Four #13 CGC 7.5: GC 0.0% increase, GPA 24.9% increase

Fantastic Four #52 CGC 6.5: GC –16.0% decrease, GPA 21.4% increase

Flash #137 CGC 8.0: GC 33.3% increase, GPA 1.7% increase

Incredible Hulk #1 CGC 1.5: GC 0.0% increase, GPA 59.0% increase

Journey Into Mystery #85 CGC 4.5: GC 4.8% increase, GPA 45.0% increase

Justice League of America #1 CGC 4.0: GC 20.8% increase, GPA 45.1% increase

Rawhide Kid #17 CGC 3.5: GC –27.3% decrease, GPA 0.0% increase
Showcase #17 CGC 3.5: GC 0.0% increase, GPA 34.6% increase
Showcase #22 CGC 4.5: GC 25.8% increase, GPA –3.8% increase

Strange Tales #101 CGC 6.0: GC 0.0% increase, GPA 44.0% increase

Tales to Astonish #57 CGC 7.5: GC –6.9% decrease, GPA –46.2% decrease
X-Men #3 CGC 6.5: GC 45.8% increase, GPA 1.8% increase
X-Men #14 CGC 7.0: GC 8.0% increase, GPA –16.3% decrease

 

If I was to run a statistical analysis of the results from GC and GPA, I would imagine that there would be little, if any, correlation between the values.

 

I also looked at the increases from December 31, 2019 to December 31, 2020. Listed below are any books that increased/decreased by 30% or more during that time frame:

 

Amazing Fantasy #15 CGC 0.5: 33.6% increase (GPA)

Amazing Spider-Man #4 CGC 3.5: 39.4% increase (GPA)

Amazing Spider-Man #5 CGC 4.0: 35.0% increase (GPA)

Amazing Spider-Man #6 CGC 5.5: 73.1% increase (GPA)

Amazing Spider-Man #9 CGC 5.5: 34.1% increase (GPA)

Amazing Spider-Man #101 CGC 6.5: 56.3% increase (GPA)

Amazing Spider-Man #129 CGC 6.5: 53.5% increase (GPA)

Amazing Spider-Man #194 CGC 9.4: 58.3% increase (GC)

Amazing Spider-Man #300 CGC 9.4: 83.3% increase (GC), 109.3% increase (GPA)

Amazing Spider-Man #361 CGC 9.4: 58.3% increase (GC), 47.9% increase (GPA)

Avengers #11 CGC 6.5: 35.0% increase (GC)

Brave and the Bold #1 CGC 3.5: 42.5% increase (GPA)

Daredevil #1 CGC 6.0: 72.5% increase (GPA)

Daredevil #7 CGC 6.5: 58.3% increase (GC), 55.2% increase (GPA)

Fantastic Four #1 CGC 2.5: 31.5% increase (GPA)

Fantastic Four #2 CGC 3.0: 63.3% increase (GPA)

Fantastic Four #3 CGC 4.0: 33.3% increase (GC)

Fantastic Four #5 CGC 2.5: 51.7% increase (GC), 60.0% increase (GPA)

Fantastic Four #6 CGC 3.5 (C-1): 100.5% increase (GPA)

Fantastic Four #52 CGC 6.5: 44.8% increase (GC), 65.4% increase (GPA)

Flash #123 CGC 4.5: 38.1% increase (GC), 52.5% increase (GPA)

Flash #137 CGC 8.0: 33.3% increase (GC)

Green Lantern #1 CGC 4.0: 40.6% increase (GPA)

Incredible Hulk #181 CGC 8.5: 35.6% increase (GPA)

Justice League of America #1 CGC 4.0: 45.0% increase (GC), 73.1% (GPA)

Justice League of America #13 CGC 7.5: –32.6% decrease (GPA)

Showcase #6 CGC 3.0 (C-1): –30.8% (GC)

Showcase #17 CGC 3.5: 34.6% (GPA)

Showcase #37 CGC 5.5: –49.1% decrease (GPA)

Tales to Astonish #59 CGC 6.5: 30.0% increase (GC)

Two-Gun Kid #60 CGC 5.0: 53.3% increase (GC)

X-Men #1 CGC 3.0: 51.8% increase (GPA)

X-Men #3 CGC 6.5: 52.2% increase (GC), 60.5% increase (GPA)

X-Men #4 CGC 6.0: 30.0% increase (GC), 97.9% increase (GPA)

X-Men #12 CGC 6.5: 62.5% increase (GC), 74.3% increase (GPA)

X-Men #14 CGC 7.0: 80.0% increase (GC), 53.8% increase (GPA)

 

I know some of you are thinking, “Why did he bother to do this?” As a former math teacher, I love working with numbers. This is a labor of love. I also hoped that it would generate some conversation. Perhaps you have seen some different trends than I have.

[piper]

Let’s see some graphs!

What do you conclude from the data?

Why the big discrepancy between the two websites?

 

[Math Teacher]

24 minutes ago, piper said:

Let’s see some graphs!

What do you conclude from the data?

Why the big discrepancy between the two websites?

 

@piper, that make take a while. I worked on this for some time today. I would like to do a statistical correlation between the value of the two sites, but I am going to have to teach myself how to do that in Excel. I knew at one time when I was teaching Dual Enrollment Statistics, but that was 2.5 years ago.

As for the discrepancy between the two sites, I believe that GoCollect uses only Ebay sales, but GPAnalysis uses both Ebay sales, as well as sales from other sources.

I think we all knew that the following books were seeing a dramatic increase in price:

Amazing Spider-Man #300, Amazing Spider-Man #361, Daredevil #1, Fantastic Four #5, and X-Men #1. And I knew Black Knight #1 was due for a fall, because its rate of growth was unsustainable.

However, there some that I just can figure out. What led to the large increase for ASM #6, the first appearance of the Lizard? He was already used as a villain in one of the Andrew Garfield movies, and surely they can't be considering him for the Sinister Six, can they? Another one that I don't understand is JLA #1. It increased by 45.0% to 73.1%, but BatB #28 either decreased by –9.4% or increased by 0.6%. You would think you would see the same type of growth for both books, since they are so closely related. Perhaps some people feel that JLA #1 is a more affordable book.

[piper]

@Math Teacher, I think prices are up just about in all keys at this point. Many people have disposable income (myself included) since many of our discretionary spending outlets are gone. Perhaps too much idle time too?

I spent way more on books than in a normal year. Is that likely to continue once things open up? I would suggest No. Once travel opens up, I plan to take the family on a trip to somewhere tropical. That will put a damper on my spending. I’ll be back in the mode of selling books to help fund the hobby.

[KCOComics]

56 minutes ago, piper said:

@Math Teacher, I think prices are up just about in all keys at this point. Many people have disposable income (myself included) since many of our discretionary spending outlets are gone. Perhaps too much idle time too?

I spent way more on books than in a normal year. Is that likely to continue once things open up? I would suggest No. Once travel opens up, I plan to take the family on a trip to somewhere tropical. That will put a damper on my spending. I’ll be back in the mode of selling books to help fund the hobby.

I think comics are due for a little bit of a correction as people start to open up their budgets for other activities. 

Not to say prices will crash, but like you, I'm planning to take my family on a big trip that will eat into comic book spending. 

[bpc3qh]

This is stellar! Thank you so much for this; I'd do it for my own books (or at least my keys) if I had the time. The Avengers 8 data is interesting, as my impression was that that book has been very hot. Perhaps it's just company data tracking weirdness?

[alexgross.com]

4 hours ago, Math Teacher said:

 

As for the discrepancy between the two sites, I believe that GoCollect uses only Ebay sales, but GPAnalysis uses both Ebay sales, as well as sales from other sources.

.

this is not correct-- gpa does not use comiclink data in any way. gocollect factors in the sales prices from comiclink to their FMV though they are not allowed to directly display results as CL considers them proprietary data (ridiculous). both sites incorporate heritage auctions sales results, which are significant as those are often the best presenting examples of keys compared to ebay where there are books of every quality level being sold. 

it's nice that you take the time to do this, thank you. as piper and everyone on the boards has noted, most books are up a lot this year and some keys, like xmen1 or ff1, are up ridiculously since autumn. 

Edited January 2, 2021 by www.alexgross.com
correction

[Spaceguy]

GPA enters Heritage and ebay auction results very quickly.  I've purchased GPA for the first time this year and was surprised to see Heritage or ebay sales listed on the GPA site a day or less after the sale.  GC is much much slower.  This could account for your discrepancies between the two particularly where a book has an infrequent sale.

[electricprune]

3 hours ago, piper said:

Let’s see some graphs!

What do you conclude from the data?

Why the big discrepancy between the two websites?

 

Some pie charts and SWOT analysis would be great too.

[Math Teacher]

33 minutes ago, www.alexgross.com said:

this is not correct-- gpa does not use comiclink or comicconnect data in any way. gocollect factors in the sales prices from comiclink to their FMV though they are not allowed to directly display results as CL considers them proprietary data (ridiculous). both sites incorporate heritage auctions sales results, which are significant as those are often the best presenting examples of keys compared to ebay where there are books of every quality level being sold. 

it's nice that you take the time to do this, thank you. as piper and everyone on the boards has noted, most books are up a lot this year and some keys, like xmen1 or ff1, are up ridiculously since autumn. 

What about other sites, such as MyComicShop.com and Reece's Rare Comics, to name a few? I was not stating this as 100% fact.

[Math Teacher]

48 minutes ago, bpc3qh said:

This is stellar! Thank you so much for this; I'd do it for my own books (or at least my keys) if I had the time. The Avengers 8 data is interesting, as my impression was that that book has been very hot. Perhaps it's just company data tracking weirdness?

I am not sure about that. I just assumed that interest in this book has somewhat waned, after the price had risen dramatically after some movie facts/rumors.

[Math Teacher]

1 hour ago, electricprune said:

Some pie charts and SWOT analysis would be great too.

I have heard of SWOT before, but, at least in first-year Statistics, which is what I taught, that's not a topic that was addressed. At least for me, it usually revolved around measures of central tendencies, representing data graphically, probability, confidence intervals, and hypothesis testing. If you want SWOT analysis, you're going to have to look elsewhere.

Edited January 2, 2021 by Math Teacher

[MGsimba77]

51 minutes ago, www.alexgross.com said:

this is not correct-- gpa does not use comiclink or comicconnect data in any way. gocollect factors in the sales prices from comiclink to their FMV though they are not allowed to directly display results as CL considers them proprietary data (ridiculous). both sites incorporate heritage auctions sales results, which are significant as those are often the best presenting examples of keys compared to ebay where there are books of every quality level being sold. 

it's nice that you take the time to do this, thank you. as piper and everyone on the boards has noted, most books are up a lot this year and some keys, like xmen1 or ff1, are up ridiculously since autumn. 

GPA reports sales from comicconnect. I'm pretty sure they always have. I was just looking up x-men 94 in 9.6 in which the last data point was an auction on comicconnect. Same thing with x-men 100 in 9.8

[electricprune]

7 minutes ago, Math Teacher said:

I have heard of SWOT before, but, at least in first-year Statistics, which is what I taught, that's not a topic that was addressed. At least for me, it usually revolved around measures of central tendencies, representing data graphically, probability, confidence intervals, and hypothesis testing. From what I saw when I looked SWOT up, it didn't into the category of mathematical statistics; it seemed more focused on opinions and solutions.

Yes, it would give you an idea of the strengths and weaknesses of your collection, opportunities to make it better, and threats of possible future devaluation.

These will be due next Friday and account for 20% of your overall grade. Line charts and bar charts will offer a one point extra credit each. 3D graphs will be 2 points each.

[MGsimba77]

24 minutes ago, Math Teacher said:

What about other sites, such as MyComicShop.com and Reece's Rare Comics, to name a few? I was not stating this as 100% fact.

Yeah GPA reports data from those two. Infact they hyperlink the sales from mycomicshop the same way they do with heritage. 

[Math Teacher]

4 hours ago, piper said:

Let’s see some graphs!

Here you go. I have 118 CGC comics in my collection. I ran a correlation on this data, and I found it to have a VERY strong positive correlation of 0.975.

The first graph is a scatter plot of the data. The horizontal axis is GoCollect prices, and the vertical axis is GPAnalysis prices. As you can see, for lower prices books, GoCollect and GPAnalysis have little difference between their values. As you can see, there is much more variance as the prices increase.

This next graph is a bar graph. Red bars represent GPA prices, while blue bars represent GC prices. Again, as you can see, the discrepancies between prices varies quite a bit as the value of the prices increase.

 

 

Edited January 2, 2021 by Math Teacher

[bpc3qh]

1 hour ago, Math Teacher said:

I am not sure about that. I just assumed that interest in this book has somewhat waned, after the price had risen dramatically after some movie facts/rumors.

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.

[Callaway29]

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

[alexgross.com]

1 hour ago, MGsimba77 said:

GPA reports sales from comicconnect. I'm pretty sure they always have. I was just looking up x-men 94 in 9.6 in which the last data point was an auction on comicconnect. Same thing with x-men 100 in 9.8

my bad, it's just comiclink whose data they do not incorporate. 

[piper]

45 minutes ago, Math Teacher said:

Here you go. I have 118 CGC comics in my collection. I ran a correlation on this data, and I found it to have a VERY strong positive correlation of 0.975.

The first graph is a scatter plot of the data. The horizontal axis is GoCollect prices, and the vertical axis is GPAnalysis prices. As you can see, for lower prices books, GoCollect and GPAnalysis have little difference between their values. As you can see, there is much more variance as the prices increase.

This next graph is a bar graph. Red bars represent GPA prices, while blue bars represent GC prices. Again, as you can see, the discrepancies between prices varies quite a bit as the value of the prices increase.

 

 

Thanks! I’ll dig into this tomorrow.