The famous Bitbag interview has the following response: "BW: We regularly go back and fine tune our data when we get fresh information so yes, on older games the data should be close to 100% accurate." In other discussions I came to understand that VG adjusted the total console numbers to reflect NPD data (ie. if VG under/overstated monthly numbers in comparison to NPD the month was adjusted up or down after the fact to reflect the NPD numbers). Yet in the last couple of weeks that does not seem to be the case.

VG made a "Press Release" stating that PS3 had surpassed 5M (VG posted the total PS3 sales at 5.07) in sales the week of 10/13. Subsequently NPD numbers came out and VG PS3 sales were 33k higher than NPD for September. So if VG is adjusting their numbers based on "fresh information" I would expect to see the PS 3 sales adjusted down - given that NPD has a much larger sample and is most likely more accurate.

Today the PS3 sales number is at 5.13M meaning the PS3 has sold 90K units in 10 days - 60K over the prior number and another 33K to make up the shortfall in Septembers number (I am giving the benefit of assuming that VG did not overstate PS3 sales for the week of 10/13 ... ). I find that hard to believe - a tripling the prior months weekly average?

BTW - 360 total units were at 11.84 for the week ending 10/13 ... the current number is 11.87 ... even though VG's September 360 sales were understated by 58K??? So somehow the 360 has lost sales in the past 10 days ...

Could we get some clarification of the Methodology behind the total console sales #"s? Are they adjusted to NPD numbers or is it just a running total of VG numbers with no adjustment?

For clarification - the NPD September data came out after VG posted the 10/13 numbers and "Press Release".

Edit - the numbers seem to be changing rapidly today - now th ePS3 is at 5.12M and the 360 is at 12.12M ... 

Are you talking about worldwide or in America?

He adjusted them for all the systems today. The ps3 was at 5.13 yesterday then it got sales of 23k for the week today and now the numbers are 5.12 which is a 30k decrease.

360 got sales of 126k and the sales numbers were adjusted upwards by over 200k because of the fact he under tracked it by 70k in September and adjusted the first 2 weeks of October to fix the under tracking trend.

Wtf? I dont get it? Amazon sales increased, and the ps3 sales dropped to the 20k range?

 The ps3 sales have always been in the 20k range for america.  In case you forgot, ioi over tracked the ps3 last month REMEMBER?  Now he's adjusted them down to match the pathetic 119k total over 5 weeks and adjusted October to match the trends.  

119k/5 = 23k a week 

Amazon is in no way an accurate gauge of the market leo-j.

Yea I guess your right.. The silver daxter psp is #1 right now..It cant be.

Still though s3 sales didnt even increase..

NPD only does USA and Canada. Those are released seperately so people often think NPD USA is comparable to VGC America, which it isn't....VGC America is for USA, Canada and possibly (though i am not certain) Mexico.

Ignoring that, all the number you gave were for VGCs worldwide totals, which have nothing to do with anything NPD has.

Any revisions in numbers might not necessarily equate to differences between NPD and VGC, mainly because revisions often occur in multiple places, so although the 360 American numbers have been moved up for the past few weeks data, they may have been lowered in 'others' (although now that it says 12.12 i am doubting it)

PS3 numbers have been recently lowered for both America and 'others' regions (last week had PS3 above Wii in 'others' but it isn't anymore)
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Basically you can trust ioi to get a pretty good image of how sales are in America, and they are revised should large discrepancies occur between here and NPD. In Japan the numbers here rarely seem to need major revisions, partly because Japan i guess is easier for ioi, but also because other companies release weekly data often around the same time as on here.
'others' numbers are much more volatile, and subject to change at any time, and sometimes extending back for a number of weeks, but they really are the best you can get for those regions, with it being so complex to track there and the dedicated companies not releasing information on any regular date.