Just a question... it is the launch for CoD:MW2? It is... so look at the October ranking.

http://www.amazon.com/gp/bestsellers/2009-10/videogames/ref=zg_bs_tab_t_bsar

Voilá... I know MW2 was to be here in October before the launch... and it is #1.

NPD shows everything (including sold by preorders in previous month) in the launch month... Amazon shows the preorder in the month it was made.

I already explained that... launch months you need to account previous preorders to compare with NPD like PS4 in November 2013.

Another example that supports my OP.

The 360 outselling the Mario... same... you have the Limited 360 Modern Warfare 2 bundle in September and October ranking that NPD just counted in November.

Wii above it? Same here... you need to look at the preorder sales in previous months to see that MW2 outsold everything in November.

So what we have for MW2?

August: #37 (preorder for November)
September: #20 (preorder for November)
October:  #1 (preorder for November)
November: #4 (sales in November)

I was tracking Amazon for so much time before make this thread to knows it works I use this example for the OP.

OP updated with the Launch + Preorde exeption... Amazon high accuracy explained for these cases... I will add the multiple SKUs exceptions late too.

For now nobody found a examaple that didn't fit in these exceptions and disprove my OP theory (close to fact already).

LAUNCH + PREORDERS EXCEPTION

In easy terms NPD shows everything sold, including the preorders in previous months, in the launch month but Amazon shows the preorders in the month that the preorder was made.

So it won't be accurate in the launch month for hardware and software because you need to look the previous months to have the real ideia of how the game/console performaned in the launch month.

Eg.

MW2 (360) > SMBWii in NPD November
SMBWii > MW2 in Amazon November

Now look the places of MW2 (360) preorders in the previous months in Amazon...

August: #37 (preorder for November)
September: #20 (preorder for November)
October:  #1 (preorder for November)
November: #4 (sales in November)

Overall the Amazon shows what NPD shows when you check the previous months preorders.

Same happened with PS4 vs Xbone in November NPD... PS4 > Xbone but Amazon November had Xbone > PS4 because PS4 didn't have any unit to be sold in November anymore... all sales are preordered in previous months before November.

Lol ethomaz. He probably has spent hours going back to each month trying to prove you wrong when all he was to do is wait two weeks for NPD and just accept that amazon can be fairly accurate or confirm that it is not. He might have tobgo back to 2008 and 2007.

It had some issues (exceptions) like the preorders in launch months or the multiples SKUs (3DS have over 20 SKUs that put they low in the racking because every SKU account for sales).

I know there are some games it won't work because promotion/dels in one retail and not in Amazon for example.... or promotion/deal in Amazon but not in others retail.

But Amazon ranking hold a pretty good accuracy even for software.

I'm sure @Kasz216 found way more examples that supports the OP than examples that didn't supports the OP while digging until 2009... I found more too but I just think a bit waste of time listing every single example that supports the OP so I decided to focus in hardware with PS4 x Xbone alone.

You could also go into a Gamestop and ask a GS clerk over the last few months which console sold more and most would probably tell you PS4, since it has won the recent NPD's. Does that make random Gamestop clerk an official reliable source? No. With a sample size this small and irrelevant (PS4 would have sold more regardless of where it was on Amazon) the results will be skewed. Thankfully someone else took the time to expose this for you.

I welcome you to challenge your own myth that MLB The Show was a "huge system seller" on PS3 next, please.

You read wrong because Kasz is already digging 2009 and the ranking proved accurate...

I'm waiting examples that disprove the ranking system.

The Show is May on PS4... not April.

Uh, you told me The Show IS a big system seller, which is current tense and past tense. I can see you clinging to next gen Show sales where they will be higher than normal thanks to early adopters needing something to play, but that won't erase the years and years and years of data we have on MLB The Show for PS3.

Your moving of the goal posts is mighty cute though, I wish you luck.

MLB The Show have a good fan base on PS3... a lot of guys bought it just for this game... system seller.

Same will happen with PS4.

Already said that to you so created a thread about.

We don't know the exact way they calculate the numbers, and what the difference is between hourly and monthly for example.

Most likely the current hour/month's sales are weighted high, and past hours/months sales weighted progressively lower. This means short term fluctuations can affect the rank significantly, and make it not represent the average sales, but if it consistently stays in a range for a long enough time then the rank should reflect the average sales.

If the monthly ranks feature data from past months, not only from the current month, then it's not 100% representative of who won the month on Amazon, and therefore of NPD. Again, if it stays in a consistent range month-to-month then it should be representative, but if there is fluctuation in a month then it may not.

Still the Amazon ranks have a fairly high rate of prediction. I don't think we should dismiss them as a data point just because once in a while it's not indicative. VGC is often not predicting on target either.