@Mars, what does it matter.

VGChartz info has always been within the realm of objectional reason to what the actual manufactorers state as global sales. When MS said they sold 17.7 world wide. VGC was about 1-1.5m less. Sounds about right, there could easily be that many sitting on shelves or trucks around the world. Maybe VGC was off a little, but so would be any other tracking firm as it is impossible to know down to the exact unit sold to consumer.

Everytime Media Crate, NDP, or any other tracking firm posts numbers VGC is not that far off. For all intents and purposes this is as good as it gets. Just because it doesn't match what you want, doesn't make it wrong.

Facts:
Wii is killing everyone and is around 20m sold to consumers.
360 is a strong second and is around 16m sold to consumers.
PS3 is doing ok for a 1st year machine and is around 9m. Actually sold about 2m more than 360 did in its first year.

That is the same ballpark you would get from any summation of the various regional sales tracking firms. If you don' believe it, sum it up yourself.

What I find the absolute funniest is - how I was doing a story on Madden and I used vgchartz as a source for the numbers and this guy from the NPD bashed me and said 'You should contact the NPD for software numbers. We'll give them to you.' What's funny is, when I asked him for numbers, he was like 'We don't have them yet.'

Haha ... you tell me that you'll give me numbers for free - then tell me you don't have them available. Sorry, but that affirmed my stance on vgchartz. Please, naysayers, show me a site that offers consoles numbers as fast as here for free. And even if ioi is off a bit, he corrects them.

Sorry, but when I ask folks for weekly gaming numbers, they are as clueless as the U.S. ambassador to Iraq addressing Congress.

If I remember correctly, it's that there was somthing about Indian sales but that it was PS2 with half a million, not PS3.
However I don't think Mars will listen.

I see the VGC bashing from time to time and if i see BS, misconseptions or someone not understanding how things work/how things are, i usually correct them. I think the time i defended VGC was today. People were talking about the 17,7 360:s sold and how VGC shows only 16. The other thing in the same topic was Wii numbers in VGC and how Nintendo couldn't have shipped that many.
So, i explained the channel and how it works, i calculated the number of Wiis manufactured using Nintendos official announcements and i explained how VGC gets its numbers and when and why VGC corrects them and where VGC usually undertracks/overtracks sales.

So the problem in the OP is pretty familiar for most of us, but luckily the easy part is to prove how accurate VGC actually is by using facts, by comparing tracking companies numbers and VGC numbers and by comparing the official shipped numbers for VGC numbers. I usually say that people should get familiar with VGC before trying to bash it.
Anyway, VGC is the most accurate tracking site i know of, the professional tracking companies may have more accurate regional numbers, but VGC offers WW numbers, which actually make it more accurate than NPD or Famitsu or Media Create. And VGC numbers are free.

@ioi: There's actually a lot less to fight than 6 months ago... There are starting to be a lot more "believers" out there, than just us, the VGC members. You're doing a great job, which really can be proved by using the facts i mentioned above. And if you remember that VGC has certain error marginal, you could say that VGC is very accurate within that marginal. Keep up the good work. Oh, and i too love the forums on the site, there are a lot of people with good views, opinions and knowledge of the industry and the best thing is, that how civil and mature (usually) the discussions are.

@All: If someone has the time and effort, could someone dig up all the discussions we have had, where we compare outside numbers to VGC numbers througout the year and make a topic to website discussion, where all the topics are linked to the first post. It would be easy to link that topic to a "VGC bashing thread" on some other site to show how accurate VGC is compared to others and to the "shipped" figures.

I'm often having to defend this site on other forums like HighDefDigest.com, and I find myself often having trouble doing so, because, to be honest, I'm not really sure what methods are used by ioi/TheSource.

From the way I understand things, ioi and TheSource estimate the American weekly numbers, and update them to coincide with NPD at the end of each month. For Japan and the EU, they use GFK, Media-Create, Famitsu, etc.

However, I tried to argue this point with someone at HDD, and they said that the ps3 figures for VGChartz were off by over 500,000 compared to the NPD tracking thread on NeoGAF. (This was over a month ago, so I'm not sure how holiday weekly sales could've factored in to this.) I tried to find this thread on NeoGAF, but couldn't, and I had a hard time debating this person without too much concrete information.

Anywho, I keep hearing talks of a "methodology page" on here. Could someone give me a link? It would be really helpful when defending this place on other websites.

Guilty as charged. Defending this site is one thing I do not do.

Google VGchartz methodology

I actually had trouble finding it too, I thought it was on the front page originally. If that was the case, then why take it down?

Btw, that's not how he tracks. ioi uses a method called extrapolation from the data he's provided. He does not adjust just because of NPD's numbers.

 Psychology indeed..

 use their financial report.