Global Market Price calc from The Undermine Journal for Wowhead

method.md

Global Buyout Price Calculation

for Wowhead, via The Undermine Journal

Definitions

• "Market Price": The cost, per each, to buy the cheapest 15% of the total available quantity of a given item at one instant in time on one realm.
• "Current Price": The market price at the most recent data snapshot.
• "Mean Price": A mathematical mean (or "average") of market prices. Sum up all the prices, divide by the count of prices. Simple. This could use the prices of one item on one realm over time, or the current prices of one item across all realms in a region.
• "Median Price": The midpoint of a sorted list of "market prices". This could use the prices of one item on one realm over time, or the current prices of one item across all realms in a region.
• "Global Price": The average value of the US and EU region median prices, as observed 8 times across the past 24 hours.

Examples

Market Price

There are 4 auctions for Peacebloom on US Kil'Jaeden:

• 5 Peacebloom at 4.50g each
• 6 Peacebloom at 6.00g each
• 6 Peacebloom at 7.00g each
• 40 Peacebloom at 9.00g each

Total quantity = 57
15% of 57 = 8.55
Market price = Cost per each to buy at least 9 (from the cheapest per-item auctions) = (5 * 4.5 + 6 * 6.0) / (5 + 6) = 5.3182g

Median Price

Peacebloom is sold on 10 US realms, with the following market prices on each:

1. 0.5g
2. 0.75g
3. 0.8g
4. 1.15g
5. 1.2g
6. 1.4g
7. 1.8g
8. 2.0g
9. 2.1g
10. 8.0g

US Median price = (1.2g + 1.4g) / 2 = 1.3g

Global Price

US Median prices in past 24 hours = 1.70g, 1.65g, 1.90g, 1.80g, 1.80g, 2.00g, 1.50g, 1.80g
EU Median prices in past 24 hours = 1.81g, 1.80g, 1.21g, 1.67g, 1.69g, 1.90g, 2.10g, 1.67g
Global price = average of observations above = 1.75g