The only number I feel NDP got right was the Wii HW. They were too low PS360, I think this proves that they were too high in the Past, and they do adjust their numbers, they just add or sumbtract from the next month.
About the GTA4 numbers, is it possible that the 6 million number could be shipped? I do remember seeing massive stock sitting on store shelves the days after launch. Because that would make sense, 5 million sold to customers six million sold to retail (massive stock on store shelves). I have to beleive the GTA number more than the others since we cant say that they were "adjusting", however I would not be suprised if GTA4 "seems" to have good legs in may(small drop because of NDP adjustment).
The MKWii number feels good, could be a tad low(on VGC). I think the SSBB number is trash.
Remember last month when VGC was 1 million or so low for SSBB? Maybe it was more like at the most.... Now NDP is "adjusting" - So basically if ioi calibrates SSBB to a lower scale he will begin undertracking.
VGC should take the 200k "overtrack from this month" and reverse the 200k of the adjustments for last month.
Dude, are you aware they have direct data from around 60% of the market? Their margin of error is max. 5% - if it somehow their whole staff stimated the remaining 40% (which btw, is mostly from wal-mart and they have historical data on walmart) while drunk driving at 150mph on the wrong side of the road, they might be at a 7-10% margin of error.
They didn't "get anything wrong" - that's the state of things in the USA, and that's it.
@the source: your estimations are off as much as 50% on hardware and 84% on software - while the average might be lower, the data is unreliable as we can't predict on which titles/consoles you'll be way off. I'm very happy for the existence of vgchartz but it's clear you guys *need* to increase your direct data. The 2% you have now is clearly not enough.