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Forums - Website Topics - No More Official NPD Previews!

I think the July '08 NPD Preview should be the last one here on VGChartz.

VGChartz and NPD provide (roughly) the same kind of service, though one charges for the information it releases and the other does not. They proceed via the same kinds of means: they collect what sales data is available to them and then use certain formulae to estimate the whole of sales.

Because the data NPD and VGChartz has access to are different, and because their methodology is undoubtedly different, their numbers will never match. Though NPD is known to have a larger amount of data from which to extrapolate the final tally, there is no way to know whether NPD or VGChartz is "more correct." The only way to know would be to compare their estimates against some Actual Number Sold... which doesn't exist... which is why people pay NPD to estimate.

Further, given all of this, neither NPD nor VGChartz is ever going to hit the exact numbers. It is possible, on any given month, that NPD's sources & methodology will provide a more accurate estimate, or that VGChartz' will. A larger sample size may give NPD the accuracy edge more often than not, but it's never a lock, and barring later information (shipped figures, etc.), it's nearly impossible to know which of the two services is closer at the time of the numbers' release.

Reading through NPD discussions month after month, I've come to the conclusion that the vast majority of VGChartz users neither understand all of this, nor are making any progress towards understanding. They take NPD figures as the "official" figures and then judge VGChartz numbers against it, which makes little-to-no-sense, because in any given release VGChartz numbers might well be more accurate than NPD. We just don't know (and basically can't know). NPD is older, more well-known, more accepted generally, etc., etc., etc., but none of that makes VGChartz wrong when the two disagree, with respect to any given sales estimate.

Therefore, I recommend that we discontinue providing official NPD previews, because I believe that the practice supports those who would treat NPD as being "more official" than this site. It seems to suggest that VGChartz has been studying week to week, but NPD provides the test to see how VGChartz has done for itself over the preceeding month, when the truth is that both NPD and VGChartz are engaged in the same work, and it would make just as much sense to evaluate NPD's figures based on how close they've come to VGChartz'.

Let people compare this site's numbers against any others, as doubtless they will, in the forums, but beyond that the management here should treat the numbers they provide as being as meaningful and valid as those of any other site.

Because they are.