One method to price/value white bags


#1

As you can see in the above post, @kedricos asked how much I valued a dbow.

There are a lot of factors that could potentially play into how much an item is worth. These include:

  • Rarity of the item
  • Usefulness of the item
  • Difficulty of the dungeon or boss that drops the item
  • Do you have to make a special trip to obtain the item - Not everyone goes in the shatters, but everyone does O1, so crown’s worth increases compared to A.S.S. since you have to make a special trip to get it
  • Aesthetic appeal of the item - some people want an item, because they like how it fits their set, ie. mg shield
  • Existence of substitutes - acropolis armor is almost identical stat-wise to abyssal armor
  • Rarity of substitutes
  • Price of substitutes
  • Number of people that play the class that uses the item
  • How long it takes you to acquire the item

All of these various points tie into the overall supply and demand for the item. Supply and demand are what ultimately decide the price of the item, so each of these factors will ultimately impact the price; however, that list contains a lot of variables that are pretty hard to quantify.
####As such, we will be calculating the MAXIMUM price that anyone should theoretically pay for an item, white bag or otherwise. Logically, we are answering the question “How much should I pay for an item, before it becomes cheaper for me to just farm the item?”

To do this, I will be looking at how long it takes to acquire an item (white bag or otherwise) and then comparing it to the amount of life that I could acquire in that same time by running tombs.

Firstly, I will calculate how much life I can obtain per unit of time by running tombs.

For the sake of this scenario, I will assume that the average group of 3 people in a tomb can do a tomb in 20 minutes. In this scenario, on average, I will get 1 life per tomb.

This means that if I am doing tombs, I can get life at a rate of:

  • 1 life per 20 mins =
  • 0.05 life per minute =
  • 0.000833 life per second

I will use this as a baseline.


For this example, I will be using the dbow. I am going to make the assumption that I can find a UDL dungeon in about 1 minute and 30 seconds. I can complete the dungeon in 30 seconds, from dungeon start to loot dropping. This means that I can complete UDLs at a rate of 1 per 2 minutes.

Furthermore, I will assume that dbow drop rate is 1/80, as per the drop rate tables.

Next, I am going to calculate the number of UDLs that I need to run in order to be 95% sure that I will get a dbow.

The reasoning is as follows: The chance of getting dbow is NEVER guaranteed. Therefore, even if I run a million dungeons, there is still a tiny chance that I won’t get the dbow. I would have to run an infinite amount of dungeons to ensure with 100% certainty that I would get at least one dbow.

As such, I will use 95% confidence. This is because anything less than 5% has been deemed by the statistical community to be so insignificant that it should not have an impact on your calculations, due to the rarity at which the event occurs.

In order to actually calculate something like this, you traditionally turn to the binomial distribution formula, which looks like this:

1 - b(x; n, P) = nCx * P ^ x * (1 - P) ^ n - x

or

1 - b(x; n, P) = { n! / [ x! (n - x)! ] } * P ^ x * (1 - P) ^ n - x

where:

  • b(x; n, P) is the probability of the event not happening
  • n is the number of trials that you run - aka the number of dungeons
  • x is the number of occurrences that you want - aka the number of dbows you want to obtain in those trials. For our purposes, this will always be 1
  • P is the probability of the event occurring - aka the drop rate of the dbow

However, since we are doing this where the number of occurrences we are looking for will always be 1, we can use an alternate formula that is much simpler:

1 - b(x; n, P) = (1 - P) ^ n

Plugging in the numbers from our simulation yields:

1 - 0.95 = {1 - (1 / 80) } ^ n

Solving for n gives:

n ≈ 238

####This means that if you were to run a UDL 238 times, you would be 95% confident (which is statistically about the same as 100% confidence) that you would receive 1 dbow.


Now let’s put it all together. 238 UDLs at a rate of 1 per 2 mins would take you 476 minutes (excluding the time it would take to do oryx or vault).

At a rate of 1 tomb per 20 minute, you could do 23.8 tombs.

At a rate of 1 life per tomb, you could obtain 23.8 life from tombs in the time that it takes to get 1 dbow.

Even if we assume that you somehow vaulted and kept all that wis that you got, assuming a conversion rate of 16wis per life, you would have earned an additional 16.125 life worth of wis pots.

Taking the difference yields the value that you got from the dbow alone.

As such, we get:

#The DBow is worth a maximum of 7.625 life.

So what does this actually tell us? Well, basically it says that the time you spend searching for the dbow is equal to 7.625 life if you were to spend it on tombs. In other words, if someone offers you a dbow for anything UNDER 7.625, then you MAY be getting a good deal. I say MAY be getting a good deal, because there are other factors that contribute to the actual price. If you are asked to buy it for OVER 7.625 life, then your time is better spent just farming for the dbow yourself in the UDLs.

This sort of logic can be applied to virtually every item in the game, so long as you keep in mind that it is not a price guide, it is simply the upper limit for which something should be bought for.


#2

only thing is, UT’s aren’t tradable…

That aside, this concept and the math involved is great, gave me a good read for the morning.
Well done on that!


#3

This applies to more than UTs. I could use the same sort of math for the etherite dagger, which I did here:

I just thought it would be interesting to do it for UTs, since everyone is always talking about what would happen in the event of a UT weekend, and I always bring up the point that the prices would probably be pretty high.


#4

And you were right on that point


#5

Plus, I think it IS useful, because you could compare whether or not it might be worth it spend time finding a particular white bag such as A.S.S versus just buying and using an acclaim, since they both have pretty similar purposes.


#6

Just wanted to mention, that was a more interesting lesson in economics than I ever got from a teacher.


#7

so if dbows WERE tradable their price should be 7.5l (but because of duping and just people being lucky it’d be less)


#8

yeah, because duping ruins everything, dbows = 1 dex in 2018 confirmed


#9

This… this isn’t exactly what I expected but it was impressive, good on you lol.


#10

Thank you, thank you. I kind of assume that the people that play this game don’t pay any attention to the logic behind it. It’s always nice to find someone that can at least hold an intellectual conversation about its workings.

Well, duping and a bunch of other factors that I listed. Over any sensible period of time, the price should always be below 7.5L, since if it goes any higher than that, people could just go farm one in the time that it took them to get the 7.5L. Note that it IS possible for the market price to temporarily go over this figure, but just because market price goes over 7.5 does not mean that you should pay it, as that would be against your best interests.

Another interesting reason that the price would be much lower than the calculated maximum is the effect of only having 8 inventory spaces. Most people don’t want to trade via multiple inventories, as that requires some trust or forethought. This is the reason that many skin prices never exceed 8L. It is true that some of them due, since skins are primarily traded for ubhps, but the majority of skins stay at or below 8L, because people can’t pay more than 8 pure in 1 inventory. I suspect that the actual market price without the inventory limit (pre-deca making most tradable skins purchasable for gold) is much closer to 12L.

This would be an example of what is called a supply shock, which is where there is an unnatural surge of products being sold at once. Basically, if there are a lot of goods being sold, sellers have to compete to deliver the lowest price, since few people want to overpay for a product. This leads to a reduction in the price of the good being sold.
Consequently, due to the lower price, more buyers are able to afford the product, so more of them purchase it.

In economics, this is akin to shifting the supply curve to the right, which decreases the price, but also increases the quantity sold.

Thank you, thank you. With respect to your question on the other topic “now closed,” we were discussing the best class for getting SB in void or LH. I told you that I prefer a 3/8 huntress with dbow, ctrap, hydra, and an exahp with maxed spd, atk, and dex.

To 3/8 the huntress, you will need 34 atk, 19 spd, and 19 dex. This equates to 6.625L. Assume the dbow is worth 7.5L (maximum price), hydra is 0.5L, and the exahp is 1L. Now for me personally, I like to use ctrap since I have a ton of them, many more than I need. As such, I value the trap at 0L, since I could care less if I lose it or not. You don’t have to use a ctrap. Any trap will do, so for the sake of the argument, i’ll say the trap is worth 0L. This means that my 3/8 huntress with said gear is worth a MAXIMUM of 15.625L.

Assuming you score an average of 1.5L from each halls run, which is pretty reasonable, you would break even in 10 runs. Again, this is assuming that you are paying the maximum price for dbow, and your atk, spd, and dex rolls are average. This also excludes the value that you would gain from any white bags, (1 white alone is probably worth the 15L, if not more) and also the t14 tops (again, worth quite a bit of life, probably ~6L each).

All in all, dying once every 10 runs is pretty reasonable for unmaxed hp and defense, and you should pull more than enough loot to make it well worth the effort.


#11

I hate math but I like this


#12

It’s called applied mathematics, too bad school is busy trying to drown you in theoretics


#13

It’s hard to teach people how to think. It’s much easier to teach them how to regurgitate information. That’s why we have the education system that we have.


#14

Yup, far too few intelligent people and too many too lazy to think, after all, ignorance is bliss.


#15

I’m an engineer all I use is applied mathematics. Im good at math I just don’t like it very much

In my country growing up we never learned any kind of theoretical algebra. I don’t know how about the rest of the world handles it.

Though a few years ago I have learned theoretical math in terms of sea rise and rain fall nothing wild
So it can be of some use depending on what your doing


#16

I see a few flaws in the model
a) You need to pay for the tomb keys
b) You get loot from gods while farming for the dbow
c) I think dont need a confidence interval here, its already efficent if you run more udls than it would take on average to get one.

I also think 2 minutes per udl is pretty and 16 wis per life is pretty unrealistic.

Interestic model nevertheless.


#17

It’s pretty easy to find free tombs, especially if you are in a guild.

If you are doing it right, you shouldn’t be farming the god lands at all. For example, when I hunt UDLs, I like to go to the fame train server, since the rate of UDL drop is pretty high due to all the gods that are being killed. If you try and farm UDLs yourself, it will take forever.

Simply doing 100 udls isn’t very helpful, because I find that I don’t usually get it from 100 udls. If we are calculating the theoretical maximum, we would want something that ensures we would get one - not just the mean.

Honestly, if you have ppl calling UDLs, it’s not bad at all.

Wis is 2:1 for defense. defense is 8:1 life. To be honest, I usually sell my wis 8:1 life and it works just fine, but I chose 16:1, because I don’t think many people do that.


#18

Yo IAmShuriama thats actually pretty cool

GJ


#19

Could you calculate pixie/etherite? I know you are going to get buying>farming, but I just want to see how distorted the market really is.


#20

I’m not entirely sure what the drop rates for pixie and etherite are.

Pixie would be tough, because finding a cland takes forever, so you’d have to assume you have keys. Also, since you can’t vault in between each cland, you wouldn’t really be getting that many pots from it. Plus, the amount of time that it takes to clear and get a boss varies quite a bit, and you also have to think about the drop rate of the actual boss, since I think pixie only drops from the gigacorn, which means you’re wasting your time with every other boss. I guess I would assume a drop rate of maybe 1 gigacorn per 7 mins, and that is being pretty generous. Since I don’t know the drop rate for pixie, I’m going to use the data off of here and just assume that it is the same drop rate as the respective white bag:

I’m sure this is inaccurate, but it’s the most educated guess I could make. So for pixie, I will assume 1/50 drop rate with a 7 minute interval. This equates to about 148 gigacorn kills, which is 1,036 minutes. In those clands, I will say you will bring back about 15 defense or attack pots, aka 2 life, which means:

###Pixie should be worth a MAXIMUM of 50 life.


For etherite, I will say that the drop rate is also 1/50, since i would imagine the drop rates would be about the same for a dungeon-based ST. I think that a cem takes about 10 minutes, and I tend to pull 3 rainbows from each cem that I do. 1/50 drop rate means 148 cems, which is 1,480 minutes, which is 74 tombs, which is 74 life. Since you can vault in between cems, I’ll say you pull an average of 3/16 of a life from each cem. This means that:

###Etherite is worth a MAXIMUM of 46.25 life.

It should be noted that if we decrease the drop rate to that of plague, 1/95, we get a drastically higher number, 93.125. If we increase the time it takes to do each cem, the maximum value goes up. If we decrease the time it takes to do a tomb, the value goes up; however, if we increase the average loot we get from each tomb, the value goes down.

Essentially, you can use the following combined formula to calculate the prices:

Max Value of Item = # of dungeons to guarantee item drop * ( EVL_b * T_a / T_b - EVL_a)

where:

  • EVL_a = the average expected value of loot that you will get from your item dropping dungeon (i.e. cem or cland)
  • EVL_b = the average expected value of loot that you will get from your baseline dungeon (i.e. tomb)
  • T_a = the average time it takes to complete your item dropping dungeon
  • T_b = the average time it takes to complete your baseline dungeon

Remember again, that this only an indicator of max price, not an indicator of the actual market value. It is just the market price cap.