I know no tracking company is perfect but how come vgchartz has USA sales lower then NPD for nearly every big game that was released prior to this year, but then this year vgchartz usually has identical or higher numbers than NPD. Did NPD track more then just USA in previous years or something?

NPD 2007

http://vgsales.wikia.com/wiki/NPD_2007_sales_figures

2007 software salesEdit

1. Halo 3 (Xbox 360) - 4,820,000
2. Wii Play with Remote (Wii) - 4,120,000
3. Call of Duty 4: Modern Warfare (Xbox 360) - 3,040,000
4. Guitar Hero III: Legends of Rock (PS2) - 2,720,000
5. Super Mario Galaxy (Wii) - 2,520,000
6. Pokemon Diamond (DS) - 2,480,000
7. Madden NFL 08 (PS2) - 1,900,000
8. Guitar Hero II (PS2) - 1,890,000
9. Assassin's Creed (Xbox 360) - 1,870,000
10. Mario Party 8 (Wii) - 1,820,000

VGchartz By January 5th 2008, so even a few more days then NPD and vgchartz counts hardware bundles which NPD doesn't.

http://www.vgchartz.com/weekly/39453/USA/

Halo 3: 4.3mil

Wii Play 3.768mil

Call of Duty 4: 2.45mil

Super Mario Galaxy: 2.155mil

Assassin's Creed: 1.65mil

Mario Party 8: 1.669mil

Games fluctuate from 200k to 550k higher in NPD than Vgchartz. Sadly couldn't find year total data for PS2 games or pokemon

NPD 2008

http://vgsales.wikia.com/wiki/NPD_2008_sales_figures

VgChartz up to January 3rd 2009

http://www.vgchartz.com/weekly/39817/USA/

Wii Play 5.21mil

Wii Fit 4.3mil

Mario Kart Wii 4.7mil

Call of Duty WaW: 2.58mil

Gears of War 2: 2.41mil

NFL 09: 1.75mil

So closer, but again for every single game NPD is above vgchartz by 100k or more except gears of war 2 and considering I am adding a few days of sales more than what NPD tracks for the year, shouldn't all the games be above NPD by a bit. Sadly couldnt find year total sales for GTAIV or SSBB

Sadly after 2008 I could no longer find yearly sales of games according to NPD, but if you look at monthly sales compared to what vgchartz has it for the month most of the time it is lower than NPD in 2009 and early 2010. This is for bigger games. The few small releases I checked, vgchartz sales are usually signifcantly higher than NPD. While I understand why vgchartz numbers can be higher than NPD because vgchartz counts games given out for free while NPD doesn't, why were vgchartz numbers often significantly lower in previous years but not so anymore.

Its been a lie all along O.o

how come famitsu and media create report plenty of times different sales numbers?

the differences are usually a few hundred units. This is a couple hundred thousand units.

well hundred thousand units would be most of the time impossible in Japan but ten thousand different units are certain not seldom...

I'll go with these numbers are from the days when they didn't have Wal-Mart data, and so we allowed a bigger difference between ours and theirs. Even at this point, you have to expect differences between both sources because neither has 100% tracking of the market.

Although it is strange that they are all under, and by a fairly significant number. Maybe those NPD numbers include Canada, but I doubt that.

More sources and experience is increased accuracy.

Hmm interesting find. I hope it turns out that Vgchartz has been undertracking those games cause that will mean Halo 3 is quite undertracked

I haven't looked into it in detail, but as the website you sources is a wiki, doesn't that mean it is updated by the general public.

NPD did release Canada figures back then (usually late and not many people took notice) so it's possible whoever created the vgsales wiki combined them.

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Hmm, nope just checked the first half 2008 hardware figure with another list I know to be USA only, so it probably is just USA NPD figures.

Its no secret that VgChartz sales aren't 100% accurate.
I treat all the numbers on this site as estimates. You should too.