| TheSource said: I'll speak to this. I asked ioi directly the other day how much sales coverage he has in the Americas - it is increasing constantly - but it is no where near NPD coverage. Still, the data is representative, and statistically sound because when dealing with data spread out from tens of thousands of stores selling videogames and videogame hardware across the continent, even 1% representation would equal over 1,000 stores - more than enough to have estimates for sales trends. Now, whether or not ioi is getting partial samples or full data from the retail channels he does cover is something we don't know. Statistically, the greater the sample size, the more nuance you see in trends and change. It is also possible to elimiiate gaps - for instance I would guess ioi can estimate PS2 numbers now because he has added stores that sell alot of that console still, while before the stores covered did not sell many/any PS2's, as it varies across the USA. I don't think I'm allowed to reveal the numerical estimate of retail coverage ioi thinks he has...but it has roughly doubled since he started providing the American charts, which is why the margin of error for everything was quite accurate when compared to NPD last month. He has passed what I consider the necessary threshold for accurate figures in the past few weeks, and in the coming weeks should approach a figure that allows us to see more of the aforementioned nuances that histrorically only professional agencies could provide. |
Thank you!
That's more what I was looking for. Obviously I would've liked to know more specific figures, but I can understand why that might be kept confidential. In any case, I'm curious now as to how much VGChartz' deviation from NPD numbers has changed over time.
