XanderZane said:
All the systems are undertracked in U.S. because NPD doesn't track ALL retailers. People keep saying the 360 is overtracked and it's not really since it definitely undertracked in U.S. The fact that it sales significantly more units in the U.S. means it's undertracked more then PS3 and Wii. The numbers on here will never be accurate unless VGC takes that into consideration, which I doubt they do. |
I'm pretty sure they extrapolate for Walmart and such based on quantifiable factors, like estimates of how many people go there and what percentage of goods are purchased by Walmart. They could even be overtracking by assuming too much from Walmart. They wouldn't be a very good tracking service if they didn't try to get 100% of the market.