If you haven't listened to this weeks IGN Nintendo Voice Chat, they discuss feedback from developer Renegade Kid (who made the DS game MOON) who said that NPD game sales data for Jan. was wrong, saying that they sold more then what NPD's number of below 15,000 units. Renegade said the actual sales are three to four times the amount that NPD gave, which is still low for a good game but not a total bust as 15,000 units for a launch month.

This is a little evidence if you're a VGC data supporter or a NPD data supporter, that it's all based on numbers and estimates, and since not every retailer/store in the world reports data it all has a margin of error, so even the big guys like NPD can be wrong.

Link to the podcast here.

Wow, NPD was off by x3 or x4?

That's pretty big. This should be read by everyone who thinks NPD is the final answer on sales. :P

the dev would be quoting shipped and NPD is sold...

Maybe this will show people that NPD is not the be all, end all of sales numbers. They don't cover anything near 100% of the North American market.

He didn't quote exact numbers but rather a general estimate (3x-4x), which implies that he based this data on new shipments ordered by retailers, rather than total shipments.

Exactly, retailers usually have low first shipments if they're not sure how it'll sell and based on how much retailers ordered you can estimate yourself how much was sold at said stores.

Interesting...

Indeed, some of the retailers the NPD doesn't get data from can have a profound influence on the statistics. I do think this won't be the last we hear of this.

If you listened to the podcast NPD already refutes the statement made by Renegade Kid, go figure, if your business is selling data, and you're about three to four times off, then some eyebrows are raised.

Which is one point in making this thread, some people are critical of VGC, but assume that NPD data is the final word, when it all deals with statistics and numbers, both are legit sources and trustworthy, but when you bash VGC numbers you better bash NPD as well :P

There's also the problem that they don't release adjustments to their monthly data. Maybe they adjust the cumulative total by changing later months, but either way something is wrong (either monthly data or cumulative one, or both).