| Jabbamk1 said: I understand what predictive modelling is.
But basing it on zero actual POS data makes the whole thing inaccurate and a bunch of guesses. At that point it becomes wildly inaccurate.
Compared to NPD who use actual POS data from retailers.
Your argument about NPD is wrong as well, I understand that all numbers are going to be estimates, but to say VGChartz is anywhere near as accurate as NPD is ludicrous. Using the whole "well all numbers are estimates" argument is pointless as that's blatently obvious. But when NPD are basing their estimate from actual data direct from retailers, are quoted by every major organisation and are seen as industry leading then what you're doing by saying they must be inaccurate makes no sense. I can guarantee the 90-95% number is valid. |
I said nothing about predictive modelling. This is statistical extrapolation, which is a different thing. VGChartz does have POS sales numbers. That POS data does not cover the entire market, however, and thus some sort of extrapolation must be done. VGChartz does this by factoring in other sources of data, including pre-order data, data from other tracking companies, and data from game companies themselves.
The result is that their numbers tend to be more accurate for more popular titles than for less popular titles - this is unsurprising, and most would consider it a minor problem at worst.
You keep making the claim that VGChartz doesn't use "actual data direct from retailers". Since VGChartz themselves say otherwise, I'm going to challenge you to provide evidence for your claim... especially since, as I pointed out, the strange numbers that happen when they forget to update release dates suggest that the absence of retail data alters the numbers. That is, the resulting numbers don't look anything like the "typical" numbers that such titles generally obtain. If they were "a bunch of guesses" when this doesn't happen, then the numbers when the date is wrong would still look just like the other guesses, and a naive prediction based on guesses would probably use past performance of titles in the same franchise to predict future performance. That this isn't what happens when the date is wrong suggests that there's a whole lot more nuance to their extrapolation than "they're just guessing".
And as Zuhyc said, regarding the "guarantee" that NPD covers 90-95% of the market... I'm going to need a source or a justification for that. After all, we all recall that big announcement when NPD started tracking Walmart. If NPD were at, say, 70% coverage, there would be no benefit to them to add Walmart to their set of sources. 70% is more than sufficient to get a proper sample and to permit highly-accurate extrapolation. That they needed to add Walmart suggests that there were some major holes in their data, and the fact that a Sega rep has explicitly said that NPD aren't as accurate as people think means that the actual coverage isn't nearly as big as people think...
So, on that point, I'm going to challenge you to put up or shut up.
