bluesinG said:
Loads of statistical estimates, right? |
You cannot estimate statistics. Since no company has the data from every existing shop, one always has to scale what one has to 100%. How you do that depends on many factors (I could quite precisely estimate Swiss data to high precision just by having the data from all the 5 Mediamarkt shops. Those 5 shops happen to contribute about 50% to the data and the remaining 100 shops add in a linear pattern to the end result..) Given that NPD, for example, has 60% of the data (and have historical data from >60% shops), that scaling may lead to a confidence level of 5% in their case.
Many people here bicker that "NPD does not have Walmart data" - so what? I'm pretty sure that a large company like NPD has the means to get close to some of that data (after all, we know that WM employees are so highly paid that none of the employees would give out some data occasionally..). Maybe they even get the direct shipment data from Sony/MS/Ninty themselves to WM in order to improve their scaling formulas. Who knows the contents of the contracts between those companies or what steps NPD takes to get to the missing data? MS/Sony/Ninty are still subscribing to NPD, so their do not seem to stray off too far from the truth.
(And as I have noted in another thread, in EU/other VGC slightly overtracks PS3 and undertracks XBox360, and overtracks XBox360 in NA (the simple fact is that both consoles offer essentially the same things to the public and therefore sell at very similar rates. Forget about that silly "this is Sony/MS country". But in the end we are talking about 1-2% numbers that are off, so who really cares...)
