I think the goal of the site is to be within 10% of actual values. Week to week there might be fluctuations, but LTD, VGC compares favorably with shipped numbers.

I think its usually pretty accurate.

Its accurate enough to get a broad understanding of the market as it is and where its going. The reality is you wont find a completely free resource as good as this site that shows worldwide numbers each week. The fact that this site adjusts its data all the time to ensure accuracy (unlike other trackers which make up the difference in the months afterwards if an error is made) is another advantage that it has.

Pretty close, They also adjust the numbers when required.

Like everyone else said, Hardware numbers are very accurate when compared to the figures Nintendo/Sony/Microsoft releases. Software, like TheSource said is harder to track but they are still usually within 25% in the worst case (excluding outliers, excluding incompletes which are usually older games).

@DirtyP2002 - unlike the NPD, VGChartz adjusts their numbers when they get better data. It doesn't prove much to compare month to month VGChartz data to NPD data as a few weeks later numbers may be adjusted. While NPD gets way more data than VGChartz they still use heavy extrapolation to arrive at their estimates. The only real way to gauge the accuracy of this site is to match it up to official shipped figures, which like has been proven match up quite well.

i have one more question. who are the moderators and how do they get paid?

better than the npd

It's funny how the fairest evaluation comes from the source (who happens to be named TheSource)... Nice work.

I think the site does the best job possible given who runs it (normal people).

I think however that there are a couple of issues that need to be addressed, with the biggest being the continuing overtracking of the 360 and undertracking of the PS3.

But sales isnt an exact science, so one cant have too many complaints

It's the best of its type.

Japan numbers = spot on. Famitsu/Media Create being close makes sure of that. Within 5%.

America numbers = very close. Within 10% usually.

Others = Not very precise. I'm guessing within 15%.

Those are weekly btw. For LTD, Nintendo, Sony and Microsoft keep on proving us close. But that's a bit because ioi isn't to proud to change the numbers. Therefore, I believe LTD numbers might be more precise on VGC than on NPD.