You can only channel stuff so much before people figure it out, Wii is easy because 90-95% of what they ship sells, MS can only stuff so much a million plus tops and by then it'll be public knowledge, ioi can take that information into account, plus he can see how much is on the shelves of the retailers he samples and project how much is on the shelf world wide

Must be accurate? Says who? Who monitors NPD, or gives them any competition - to make sure that they don't get lazy with their figures?

(for all WE know, NPD talks to the platforms holders - and verifies that their numbers aren't WAY out before publishing them). 

I very much doubt that a company is going to purchase the NPD figures - have a read - then say "We want our  money back - we don't like your numbers!". Competition is much more likely to hurt NPD, than for them to release dodgy numbers.

In hindsight, I agree that if we start changing our figures to match NPD - we are meaningless. We need to position ourselves as an independent tracking body - basically competition to the NPD.

Just like Famitsu & MediaCreate in Japan end up with different numbers - so can our numbers vary from the NPD figures. 

...

If NPD really doesn't track/count "bundled" software, then it does mess things up - and make it hard to directly compare. Add to that, that VG tracks all of NA (etc).

Oh come on what does NPD have to obtain by messing or posting bad numbers. What would they gain? Apsolutely nothing. It's not like they only have one of the major 3 receiving their numbers. They have all 3. Meaning if they screwed up their numbers in any which direction they'd only be losing consumers.

To keep its major consumers NPD has to get the most accurate numbers as possible. If they distort them or don't check their numbers they only people they hurt is themselves. They may have a monopoly but that monopoly is in check by its consumers such as Nintendo, Sony, and MS. If they don't give out the most accurate numbers they can possibly give then they'll lose consumers such as them 3. Yall act as if this corporation is purposely out their giving us false numbers to make fools of us all.

Doesn't the released top 10 include both versions of Guitar Hero for the PS2? Didn't SimExchange claim to have access (under their agreement with NPD) to the data for both versions of Guitar Hero for the 360? Either the numbers posted on this thread (and on SimExchange, I checked those) are bogus, or Guitar Hero pretty much disproves that theory.

The aparent numbers for Guitar Hero see VGChartz with NPD+60% for the 360 and NPD-50% for the PS2. Who's right? I don't know. And I respect the decision not to change the numbers. But still, it's a big difference, and it doesn't seem to be explained by that theory.

Calm down, we are just saying they are not necessarily accurate. I am also not sure where you get all major 3 correcting their number, you do realize company usually have trade secrets that they'd rather not reveal, right? 

How accurate do they really have to be Zucas, on a monthly basis they can be more off than you seem to think without any concern, they can chalk it up to eroor based on sampling, not to mention they also don't have anyone checking them on a constant basis to tell them if their data is off, no one's saying that they totally pull numbers from thin air, but you shouldn't believe that they are 100% accurate

Guys everyone here doesn't give NPD enough credit for the accuracy of their data... they would have to be accurate.

The reason for NPD is because they collect all of the information from competitors...

You don't think that Nintendo, Sony and Microsoft track what retailers sell themselves??? You've got to be kidding.  They have accounts with all retailers, and the retailers need to order stock when they run out... they know the numbers with which they sell.

Nintendo Sony and Microsoft know what their own numbers are from retailers directly - I know this for fact - NPD then provides them with the competitor information.  If this information wasn't similar or accurate within 5 or 10% of their internal tracking numbers then they would not longer subscribe to the NPD service.

And for whoever said that NPD doesn't report weekly, please tell me your source.  Any information that I've got tells me that they report weekly to their customers... which they do.

 I never said anything about NDP customers asking for their money back when the NDP data is way off. Of course no one will ever do that but I know for sure they will stop paying for it. This means NDP's business will go down the drain.

If you guys want to be taken serious your data cannot be way off like this. It must be on the mark. If NDP and the others release their monthly data based on a much better sample than yours why don't you use use it?

 Remember, the NDP data is trusted by MS/Sony and Nintendo and about everyone else that reads it. On the other hand I keep defending VGC credibility because people make fun of your numbers on gaming sites.... oh well my bad I guess.

I kind of see what you are saying..... there are ten pies, NPD has it's hands in six of them so it knows how large all six are, but estimates for the other four pies.

VGC has a finger in 9 or even 10 pies so can extrapolate to find the size of each pie relatively accurately, thus less estimating for whole pies we know nothing about like NPD.

mmm, pie