Forum:💸CTI update💸

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Forums: Yew Grove > 💸CTI update💸
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This thread was archived on 16 June 2016 by Liquidhelium.

The common trade index is one of the wiki's earliest use of GE prices. It has even managed to retain a place on the main page!

However, the items it represents are fairly outdated now. For future reference, here's a list of all the items current on it:

Current stuff

Before we decide what to add and remove, we need to at least think about what we want the CTI to represent. As pointed out by chi pa pa, the list looks like what used to be common PKing supplies mixed with common skilling supplies. Is this what we want to continue representing? Or do we want to shift focus?

I'm going to go with a slight focus shift, moving a bit away from PvP and closer to current PvM, since that's a lot more of what RS is today. I'm going to propose a few general rules which will give guidelines on how to decide what to change. The actual changes (which items are added and removed) will be discussed in the following thread, should it be decided that we change.

Proposed rules
  • Each skill should have at least one item representing it
  • The items are commonly used in popular money-making or skill-training methods
  • There should be no more than 50 items
  • Items should not be at, close to, or past a hard or soft price minimum or maximum, and the price shouldn't be bounded by constant NPC/store prices
    • The hard price minimum is 1 coin, so pouches and empty vials are not allowed
    • The hard price cap is 2^31-1, but I don't think anything that gets close to that can be considered commonly traded
    • A soft price minimum is an alchemy price, so dragonfire shields are not allowed (alchemy price 1.2m, GE price 1.198m)
    • A soft price maximum would be, for example, applied to crystal weapons: one can buy a new crystal bow from Islwyn in the forest for 1,000,000 coins (capping the bow there), disenchanting it to a weapon seed (capping the seed at 1m too), then re-enchanting it for 200,000 coins in Prifddinas (capping the rest of the crystal weapons at 1.2m)
    • Items bounded by an NPC are sold/bought in near-infinite quantities by an NPC or shop at a specific price; examples include spirit shards, empty pouches and vials
  • Items with prices under 100 coins should be avoided, as the low prices can limit price movement e.g. items under 20-40 coins (depending on rounding) can only move 1 coin at a time which can be a large proportional price change
  • Avoid items with a significant, explainable trend/pattern in its price (consistent rising or falling), for example most tier 90 weapons are constantly falling in price as more enter the game than leave
  • Items which trade significantly away from their GE price should be avoided (say, more than 50% above or below)
  • Items should trade frequently enough that their price regularly updates; no stagnant items

Change the CTI y/n?


Support as nom Quest.png Gaz Lloyd 7:^]Events!99s 23:38, June 2, 2016 (UTC)

Soft Support - I do think the CTI definately needs updated, but I feel like some of your proposed rules are a bit too strict. --dDbvitC.pngScuzzy Betahib8CAd.png 23:54, June 2, 2016 (UTC)

>meme arrows - If it's the common trade index, where are the items that are actually commonly traded by an objective standard, like fire runes? I honestly think most of those should be on the list. I think that except for spirit shards (which are strictly and invariably 25 gp outside player trades), all these items should actually be strongly considered first. I'd personally propose the following items be on the CTI:

  • Coal
  • Fire rune
  • Air rune
  • Nature rune
  • Flax
  • Broad arrowhead
  • Magic log
  • Maple log
  • Yew log
  • Incandescent energy
  • Brilliant energy
  • Pure essence
  • Feather
  • Blood rune
  • Cannonball
  • Dragon bones
  • Shark
  • Runite ore
  • Rune bar

Just to name a few. I think the lower limits regarding price movement are mostly negated by the sheer volume of these items being traded. The CTI always did feel wrong, because I'm not sure where the idea that these items were commonly traded comes from. Sharks? Sure. They're still on the list today. But dragon boots? Sure there was a lot of pking, but it wasn't anywhere near that much. MolMan 23:55, June 2, 2016 (UTC)

Comment - I suggest we create 2 indices. A "true" CTI, which consists of all 100 of the most traded items Jagex has listed, and a second "selected" CTI based on decisions here. The latter would be some application of Gaz's guidelines applied to the larger former list. MolMan 23:58, June 2, 2016 (UTC)

I can be down with a 'Most traded index' for them top 100 (possibly excluding fixed price items like pouches, vials, and spirit shards). If we do that, do we want to rename CTI? 'Common resource index', maybe? Quest.png Gaz Lloyd 7:^]Events!99s 13:41, June 4, 2016 (UTC)
I don't think name is that important. I'd personal just call them both CTI; one "selective", one "complete". MolMan 13:44, June 4, 2016 (UTC)

from discard

uhhh i disagree with prayer potion 3
and while i get what you mean with sirenic scale
it's the rarest as well
uhhh I think what we should do first
is look at the top 100
and pick out items from there
and then fill in necessary gaps
i'm really inclined to say definitely add yew/mage shieldbows
and gwd armours
i'd leave flax on there
bowstrings are important
and they're received a lot from rdt
we may not have flax pickers, but it's traded a lot
pure essence should stay
rune armour set should go
snape grass is hard to say
i'd put steel of legends scroll ther as well
uhhh potion flasks/crystal flasks
@Gaz pls respond i feel dumb

I still feel dum MolMan 00:12, June 3, 2016 (UTC)

Support - I've been meaning to quietly update this ever since we moved to the module setup of exchange data. It's been neglected for a long, long time. What I was thinking was automating it to some extent to cover the 100 most traded items, but extending it to include common resources would be excellent as well. The only caveat is that we need to be mindful of is including things like armour and weapons which can fluctuate on a whim as new equipment is released. cqm 00:17, 3 Jun 2016 (UTC) (UTC)

Modulising it (and all the other indices) sounds like a good thing to do in this process. Quest.png Gaz Lloyd 7:^]Events!99s 13:41, June 4, 2016 (UTC)

Support - When changing the items, or even not changing them, we can/should add weights to the prices if they aren't already there, so expensive items don't statistically obscure the cheaper ones. Also, on the day it changes, the function should be continuous. Real exchange indices do the same thing when they change index components. --Saftzie (talk) 12:10, June 3, 2016 (UTC)

I'm not sure what you mean by adding weights. Do you have an example of what we'd do, using e.g. the current list? (Calculations are here.) Quest.png Gaz Lloyd 7:^]Events!99s 13:41, June 4, 2016 (UTC)
Instead of Index = (Price of A) + (Price of B) + ..., you'd have Index = (Weight of A) * (Price of A) + (Weight of B) * (Price of B) + .... Without weights, changes to the price index are dominated by changes to high-cost items, which don't necessarily reflect the economy. For example, how many fire runes are traded in a given period versus how many rune bars? Probably more fire runes are traded, so the price of a fire rune would be weighted more heavily. Of course, a rune bar still costs more, too. It would be great if we had volume data for everything, but we don't. I think it would still be good to try to assigns weights, though. --Saftzie (talk) 19:30, June 6, 2016 (UTC)
Just to clarify my previous statement, the weight for an item doesn't have to be proportional to its volume. It can be some other function of its volume. For items where we don't know the volume, we'd just have to use some kind of judgement. --Saftzie (talk) 20:45, June 6, 2016 (UTC)
We should have volume data of anything in the top 100. So ya I'm pretty great at ideas. MolMan 19:32, June 6, 2016 (UTC)
That works for the 100-most-traded index, but what about the other index for selected items? Or was the suggestion to "select" only from the list of 100? Ideally we should use a monthly volume to avoid the effect of activity (positive or negative) spikes. --Saftzie (talk) 20:45, June 6, 2016 (UTC)
If you really want to push the volume thing, then making selective only take from the top 100 is our only choice. But at that point, it makes 0 sense to have separate indices. MolMan 21:37, June 6, 2016 (UTC)
Actually I'd really be pushing the weight thing. Whether we determine weight from volume is another matter. Weight is kind of a measure of importance to the economy. What is it about the economy that we're trying to measure with the index? Are we trying to measure how much money is being exchanged in trades? If so, then volume traded makes sense. If we don't have volume data, we have to guess, which may have to be a viable option. Are we trying to measure average personal wealth? In that case the number of each index component owned by the average player would be the thing to use to determine weight. Or maybe by "economy" we mean some combination of those things or something else. Whatever it's supposed to measure, if we just add prices without weights, a Bandos chestplate + fire rune index, for example, would be essentially a Bandos chestplate index. --Saftzie (talk) 09:51, June 7, 2016 (UTC)
Guessing isn't the way to go here at all for volume. We really can't have only have of the weights be accurate and the others pulled out of our ass. MolMan 11:54, June 7, 2016 (UTC)
The guessing would be for the weights, not the volume. You're the one that seems to be hung up on volume. Again, what the index is trying to measure should determine the weights, so what are we really trying to measure? For practically anything, including volume, the weights are going to be estimates, because Jagex doesn't provide data on anything really. I suppose one possibility is that we could ask them to provide us a time-limited set of super-secret-don't-tell-anyone-how-the-market-actually-works data, although they might say no. --Saftzie (talk) 19:31, June 7, 2016 (UTC)
"If we don't have volume data, we have to guess". You literally said guessing for volume though. MolMan 19:33, June 7, 2016 (UTC)
Context matters. "Are we trying to measure how much money is being exchanged in trades? If so, then volume traded makes sense. If we don't have volume data, we have to guess, which may have to be a viable option." In the next sentence, I talked about if the index was trying to measure something else. What it's trying to measure is still a open question, since no one has answered it, much less had a consensus formed. --Saftzie (talk) 18:27, June 8, 2016 (UTC)

Closed - The CTI can be updated. Several users have suggested creating an index based on the 100 most traded items. --LiquidTalk 18:56, June 16, 2016 (UTC)