Item numbers.

[inhawaii]

I store my items in 10 bins/cabinets numbered 1 through 0 based on the last number of the item number.

If I need to pull and pack item #123456789 it will be in bin #9.

The system has been working great for me for years however lately as my listings have gone up i've noticed,

some numbers seem to  be more "popular" than others.

Bin #2 has way less items than bin #9 which is full.

Sometimes I will actually end a new listing because of the item number (full bin)

and re-list it until I get a better item number (less full bin).

My question is, do you think item numbers are generated totally at random

or will one last digit  come out more than than another?

[dbfolks166mt]

     A little math for you will give you the answer. 

[retro_entertainment_collectibles]

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@inhawaii wrote:

I store my items in 10 bins/cabinets numbered 1 through 0 based on the last number of the item number.

If I need to pull and pack item #123456789 it will be in bin #9.

The system has been working great for me for years however lately as my listings have gone up i've noticed,

some numbers seem to  be more "popular" than others.

Bin #2 has way less items than bin #9 which is full.

Sometimes I will actually end a new listing because of the item number (full bin)

and re-list it until I get a better item number (less full bin).

My question is, do you think item numbers are generated totally at random

or will one last digit  come out more than than another?

---

One thing to remember is a computer cannot actually generate a truly random number.  There are many ways programmatically whereby eBay generate item numbers and archive old listings so as numbers might be reused if'n they reuse values.

[biggymoe]

Don't understand the above, it's all Greek to me.

I think it is totally random.  You need to make another bin #9

[pennysdream]

I sort the bins by item type.  When the bin is full, I pull old stuff to make room to start a new bin.  

I do my number in numerical order, With a letter in the front.  A- 1 - 999, B-1-999.  and so on.  

This also helps me to see what hangs around way too long.  

This is the one system that I have been using since the beginning.  It is the only thing that hasn't changed.  

Oh, and zip-lock bags. Hehe 

[chris13]

When I need to mark item locations, I do something similar to what Pennysdream mentions.

When I prepare for sale I mark each envelope/box with pen by putting an alphanumeric code.

e.g. "A005"

I then add the text "SortID: A005" to the bottom of the listing text.

This tells me to look in area A (my spare room's walk-in closet) for a package marked "A005", double checking that the content does match the listing. 

[a_c_green]

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@inhawaii wrote:

Sometimes I will actually end a new listing because of the item number (full bin)

and re-list it until I get a better item number (less full bin).

---

Um, okay, that's just silly. 😉

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@inhawaii wrote:

My question is, do you think item numbers are generated totally at random

or will one last digit  come out more than than another?

---

I doubt that they're truly random, since generating them that way would require a second step of searching the universe of current listing numbers to see if the new one is already in use. For example, if I glance down my list of recently-sold items, I can see that every listing number starts with either 23 or 33, and the digits immediately following the first two vary very little, so the listing numbers are being generated from a deliberate algorithm of some kind, perhaps using subsets based on the type of listing or the category it's in or something like that, putting them together into one larger listing number. 

Finally, that last digit of the listing number might actually be a check digit, provided as a "right answer" to a verification process that might want to mathematically slam together previous groups of digits in the listing in order to verify that they still match the number that was originally generated. This might be necessary if the listing number is being handed off from one process to another, and should be verified to ensure that all the digits of the listing number are still present and correct.

So no, they're not truly random (or even close to random, from what I see), but have just enough embedded coding in the way they're generated to ensure that they each stay out of each other's way.

[retro_entertainment_collectibles]

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@biggymoe wrote:

Don't understand the above, it's all Greek to me.

I think it is totally random.  You need to make another bin #9

---

LOL.  Computers run programs, programs are made of computer operating codes and operate upon data.  There is no way inject a randomized event.  Many types of Random Number Generator codes exist but just as you might "run the generator code in you're head" none of it is random albeit might seem appear that way.  They are called Pseudo random values and again there's varied of approaching them.

eBay may or may not use pseudo randomization to generate item numbers or even partial numbers or the database software used might simply increment on each new record assuming the item number is an index value (indexes are used to rapidly find records).

That all said, mankind has been smashing atoms together in various colliders for many years now trying to create one single random event and best of my knowledge has yet to succeed.  It's theorized in a universe driven by Physics there is no such thing as random anything albeit so very complex it's not fully understood, comprehensible nor necessarily verifiable.

Aka:  A star explodes somewhere in the Milky Way Galaxy when 130 million years ago.  In doing so in changed the trajectory of a small asteroid that 10 million years later struck another asteroid.  That collision resulted in a small fragment, a meteor making it's way over 25 million years into our area of the Milky Way where in another 95 million years managed to have Earth run into it and most of it burned up into dust entering our atmosphere... However, a small little bit made it's way down and hit a tree leaf causing the leaf to fall to the ground whereby much of it degraded over time.  Some of the leaf was eaten by four different insects, then a bird picked it up and used it as part of its nest, a bee came along and took some from the nest to bring to a hive.

Nothing random there albeit ever so complex when we start breaking it all down to lowest common denominators and those not common.  But if we had all knowledge we would be able to see the physics microsecond by microsecond of all of it from the travel of said object(s), entry into our atmosphere, exactly how and what burned off, trajectory to that tree leaf from inception of said event...  Why we could even see that of the bird, from it's say 4 million year ancestral history to they very moment its brain neurons and that of all it's ancestors did what they did, and he did.

Very very very complex but explainable given all data and understanding of said data.  That said as a "smart species" we really are not too bright.  If we were to take all of the interactions that happen in you're backyard on say a rainy day all of the computing power in the world could not figure it out along with all the complex interactions if they were to run upon it 24/7 for you're entire lifetime.

[retro_entertainment_collectibles]

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@a_c_green wrote:

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@inhawaii wrote:

Sometimes I will actually end a new listing because of the item number (full bin)

and re-list it until I get a better item number (less full bin).

---

Um, okay, that's just silly. 😉

---

@inhawaii wrote:

My question is, do you think item numbers are generated totally at random

or will one last digit  come out more than than another?

---

I doubt that they're truly random, since generating them that way would require a second step of searching the universe of current listing numbers to see if the new one is already in use. For example, if I glance down my list of recently-sold items, I can see that every listing number starts with either 23 or 33, and the digits immediately following the first two vary very little, so the listing numbers are being generated from a deliberate algorithm of some kind, perhaps using subsets based on the type of listing or the category it's in or something like that, putting them together into one larger listing number. 

Finally, that last digit of the listing number might actually be a check digit, provided as a "right answer" to a verification process that might want to mathematically slam together previous groups of digits in the listing in order to verify that they still match the number that was originally generated. This might be necessary if the listing number is being handed off from one process to another, and should be verified to ensure that all the digits of the listing number are still present and correct.

So no, they're not truly random (or even close to random, from what I see), but have just enough embedded coding in the way they're generated to ensure that they each stay out of each other's way.

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Exactly, likely there is no random anything involved in item number generation.  Subsets could be "Store Index" (say an 8 bit value), another 8 bit value as category with the store "Super Category" (if you will) on and on... Many ways to tackle things.

Here for example is a partial image of the Database Schema of Media Wiki.

[inhawaii]

So i guess most of you are saying item numbers are not random.

If you were to take 1,000,000 item numbers and looked at the last digit,

one number would appear predominantly more than another number?

[chris13]

Random = 'Random enough for most'

An empty cup = 'Empty enough for most'

Words approximate using context.

[sin-n-dex]

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@inhawaii wrote:

I store my items in 10 bins/cabinets numbered 1 through 0 based on the last number of the item number.

If I need to pull and pack item #123456789 it will be in bin #9.

The system has been working great for me for years however lately as my listings have gone up i've noticed,

some numbers seem to  be more "popular" than others.

Bin #2 has way less items than bin #9 which is full.

Sometimes I will actually end a new listing because of the item number (full bin)

and re-list it until I get a better item number (less full bin).

My question is, do you think item numbers are generated totally at random

or will one last digit  come out more than than another?

---

Your strategy seems to make sense except when items are relisted with new numbers (and not moved into the right bin) and when bins are full because some numbers come up more than others.

My shelf at the B&M Store has bins, and I put the bin code on the cardboard the coin is in, so I can look in the picture and see where to find it. There is alphabetical organization, but generally I just add bins. My stamps are in similar bins, so A15 will be in the A bin, when the A bin gets full, I start a B bin, when the A bin has items selling, I add numbers where I left off to put more items in.

Kinda similar... I hadn't thought of using the item number to help find things.

C.

[Anonymous]

Y’all make it sound confusing. Perhaps too many items listed that are not or will not sell.  

[onlinecentral]

If Bin #2 is the emptiest, then add Bin #2 to the CUSTOM LABEL/SKU when you create listings.
The CUSTOM LABEL/SKU appears on the
ITEMS AWAITING SHIPMENT screen
ALL ORDERS screen
PAID SHIPPED screen

When BIN #2 reaches capacity, utilize the emptiest bin for new listings.

FYI: My inventory is stored in order by MPM or MANUFACTURER PART NUMBER in equal sized boxes arranged into stacks, rows and aisles.

[simply-the-best-for-you]

@inhawaii  It is ABSOLUTELY NOT totally random.  Don't believe me?  Pay attn to the first 3 digits of your item numbers.  Compare to your other item numbers.   You will discover that they are ALL most likely 2 sets of digits & are always those 2 sets of digits.  I discovered this easily 10+ years ago & actually did a bunch of research, involving 30 or so other users on that board, in regards to it.  We all had 2 sets of 3 digits, though they were NOT the same 2 sets for each of us.  

I was not able to fully devote the time I needed to analyzing the data & determining what it meant & what they were used for, but I have suspected for all this time (it's not really a suspicion, it's the way programming works), that those 3 digits mean something & are used to determine different things.  Otherwise, they would not always be the same & remain static for decades.  I have theories, but none I'm willing to publish 🙂  

In addition, I'm certain, just from my programming background, that other digits in the Item Number have specific meanings as well.  That's standard programming.  I do believe that some of it may be sequential (not random) & likely sequential based on other parts of the number, but IDK this for a fact, it's just likely, b/c it needs to be unique. 

Here's an example: 

052290278542

-1st 2 digits are state 

-2nd two are year

-next 3 are first 3 digits of zip code

-next 5 are sequential 

This would be a very typical way to create a unique key.  

It was years ago, probably near a decade that I discovered this & did the tests & everyone involved had either 1 or 2 sets of 3 digits that started all their item numbers.  I can't swear that's still the case, but I can say that it appears to still be true for me.  I sure wish I knew why there were 2 different ones (in my past testing, we almost all had 2) & how they are used.