Because, they just don't add up even if the numbers of sales figures are "shipped to retail" totals. NPD came out with its January figures and the 360 finished third among the big three now.

http://www.reuters.com/article/rbssConsumerGoodsAndRetailNews/idUSN1449127120080214

"During the month, Nintendo sold 274,000 Wiis, Sony Corp (6758.T: Quote, Profile, Research) sold 269,000 PlayStation 3 machines and Microsoft Corp (MSFT.O: Quote, Profile, Research) sold 230,000 Xbox 360 consoles, NPD said"

Now, looking at the weekly totals for the month throughout the month of January, it would seem that the 360 would at least break even in sales considering it "sold to retail" more than the PS3 did by a good margin. Now, I'm thinking the numbers are pure conjecture, and not from real sources, because Microsoft came out with a press release (though it may be lame IMO) saying they didn't manufacture enough SKUs because they didn't anticipate post-holiday sales to be this strong.

http://www.reuters.com/article/technologyNews/idUSN1337448620080213

"SAN FRANCISCO (Reuters) - Microsoft Corp (MSFT.O: Quote, Profile, Research) is seeing shortages of its Xbox 360 video game console in the United States, as the company failed to anticipate strong post-holiday demand, an executive said on Wednesday.

"We are really running short of product here in the United States," Jeff Bell, head of global marketing for Microsoft's games business, said in an interview. "You could say we misjudged demand."

The comments came a day before market research firm NPD is expected to release video game sales data for January and Bell said Microsoft was hoping to "manage expectations."

So, where does this site get its numbers, or are they just guesses?

it's hard to read the frontpage, i know

Where Do Our Numbers Come From?

Unlike many other websites (which use manufacturer shipment figures and reports to estimate current console sales), VG Chartz collects data directly from retailers all over the world. Retailer sample sizes are small compared to professional tracking services, but are large enough to provide very accurate projections of the latest console sell through figures worldwide. We are the only provider anywhere in the world of weekly American sales charts and are expanding our data collection and coverage all the time. To find out more, visit our about us and methodology pages.

 also : http://www.vgchartz.com/methodology.php

Have you ever heard of the hold your hand over your eyes and point randomly on a paper full of numbers technique? It seems to be working so far.

Just kidding, the last comment explained it well.

I thought the numbers came from Pachter. I don't know where he gets them. (I KID!)

that was funny. lol 

You seem to trust NPD more when basically it does the same thing as VGchartz except they use numbers given them by retailers(gamestop,amazon,k-mart, etc.) and estimate for the fact they don't get numbers from walmart corp. and Toy R Us.Meaning there is big percentage of the final number that is actually guess work. I think about thirty percent but I doubtful that is actual number. Basically what I am saying that both VG and NPD uses guesses and no on the exact number of consoles sold to consumers.

P.S If you are talking about # number sold to retailers I apolgize.

NPD does like 40% guessing, but Vgchartz does like 95% I believe.

 great..call it guessing..thats an insult for both..

I thought that VGC was about 15% coverage, and NPD was more like 60%

That's the way I roll.