Median???

How is median calculated on this site? Sometimes I see strangeness that I don't understand. My understanding of median was that it was the middle value when going by sheer count... so it is the number that has the same amount of data points above it as it does below it.

Why then am I see this? Look up Beetle Mittens +1 on Titan. Here's the data in case in changes by the time you read this...

Median is currently at 1000.

Below are the previous sales. You'll notice that a single sale was for 1k, and it happens to be the second most recent sale. EVERY other sale is much higher than 1k. How can median be 1k?

Dec. 2, 2008 Blessedangel Valerie 9,000
Dec. 1, 2008 Anslem Yangasu 1,000
Nov. 30, 2008 Lamont Linku 8,000
Nov. 30, 2008 Daffelz Anslem 10,000
Nov. 29, 2008 Angelsola Turell 8,000
Nov. 29, 2008 Weeeeeee Kryll 8,000
Nov. 29, 2008 Vanon Blessedangel 8,000
Nov. 28, 2008 Riddik Socant 8,000
Nov. 28, 2008 Halhal Donkie 7,000
Nov. 24, 2008 Antique Skyfang 8,000
Nov. 24, 2008 Maine Quma 8,000
Nov. 23, 2008 Halls Boochan 8,000
Nov. 23, 2008 Mindhunter Shunsho 8,200
Nov. 23, 2008 Hattori Popp 8,100
Nov. 22, 2008 Spert Zicdeh 8,000
Nov. 21, 2008 Nyny Laucredant 8,000
Nov. 19, 2008 Ayaha Godfrey 8,000
Nov. 19, 2008 Hilti Sonofagun 8,000
Nov. 19, 2008 Ilaunie Hilti 10,000
Nov. 18, 2008 Pocopen Orick 8,000
Nov. 17, 2008 Jorg Weeeeeee 8,000
Nov. 17, 2008 Clavia Garnetdagger 8,000
Nov. 17, 2008 Sumopwr Qumar 8,000
Nov. 16, 2008 Ophelia Sapi 8,000
Nov. 14, 2008 Gerita Exio 8,000

In fact, in every example I've looked at, the "Median" value is simply the second most recent sale price. What the heck is up with that? Am I crazy?

Tiger Hunter on Titan is another great example. Media currently reads an odd 2,360.

Previous sales are...

Dec. 3, 2008 Oxo Palesade 5,000
Dec. 2, 2008 Zeld Silversterr 2,360
Nov. 30, 2008 Slasher Hachishiki 4,000
Nov. 30, 2008 Slasher Lomyou 4,000
Nov. 28, 2008 Pifre Darkdart 4,000
Nov. 25, 2008 Hakugen Pfeffernuse 4,000
Nov. 25, 2008 Optimus Pifre 4,000
Nov. 23, 2008 Turell Oxo 6,000
Nov. 22, 2008 Waterlegend Kratos 5,000
Nov. 20, 2008 Toraneco Warlordd 6,000
Nov. 20, 2008 Tuntunmaru Nung 4,000
Nov. 20, 2008 Tuntunmaru Nung 4,000
Nov. 19, 2008 Optimus Jollymike 4,000
Nov. 19, 2008 Teretha Jollymike 4,000
Nov. 17, 2008 Zoos Tuntunmaru 4,000
Nov. 17, 2008 Friendless Tuntunmaru 4,000
Nov. 15, 2008 Junjix Souga 4,000
Nov. 15, 2008 Aqri Fushu 3,000
Nov. 15, 2008 Ryozo Chabs 3,000
Nov. 15, 2008 Digi Jerusalem 3,000
Nov. 14, 2008 Ruinator Amdukias 4,000
Nov. 13, 2008 Amulet Digi 3,000
Nov. 13, 2008 Amulet Junna 3,000
Nov. 11, 2008 Tomotoro Friendless 5,100
Nov. 11, 2008 Tamanegi Higemegane 6,000

Strangely, Beetle Mittens +1 have now switched to reading 8k... but I swear it was 1k!

Well everything seems back to reasonable numbers again. I'm not crazy, I swear. =P

lol. gotcha

Thanks for reporting. An important part of the median calculation was left out... could of sworn it was there before. As of right now, it takes the median of the last 3 transactions, good for fast selling items... bad for the slow sellers. This only applies for the Median displayed on the item pages.

Medians displayed everywhere else is a precomputed based on the last 25 transactions if I'm not mistaken.