Weird, isn't it. Just goes to show you that something that's 100% accurate can't always be trusted ... and you'd be a complete idiot to discuss this 100% accuracy outside of the Amazon thread.

*snap*

Steamspy is invaluable for digital data. I feel something identical for PSN would definitely be possible considering how PSNP works, someone just has to set up the site.

So, Someone need to sneak into Sony's headquarters and place a counter of digital activity ?.

Amazon is a great indicator, so long as you apply common sense. Last month (or was it March, can't remember) saw the MSRP drop from $350 to $300. Amazon has always been $300 for months at that point so consumers who don't shop at Amazon saw the effects of the price drop. Last month also had the GameStop trade in which likely accounted for a good portion of sales. For those who check hourly charts regularly, you could see the Xbox slowly drop as the deal took effect before bouncing back to its typical position. 

The only other month where Amazon was "inaccurate" was only if you ignored preorders from previous months. 

As long as you follow how well those pre-orders are doing then you have a 'rough' idea of who will win that month, but it's always difficult to call.

The sales splits for FFXV and KHIII are going to be extremely fun to watch.

Ah. I see. That actually might make a big difference. I wonder how much of all that decline since 2009 was due to how grossly overinflated the market was last generation. Home consoles sales were arguably way more than they would have been otherwise thanks to the Wii selling well (it was responsible for about 75% of all gen-over-gen console sales growth), and the handheld market shattered expectations, with the DS selling more at its peak than any hardware platform ever and the PSP being the first non-Nintendo handheld to perform well (the GBA also overperformed in the U.S. relative to Europe and Japan). The Wii U's struggles, the inability of the 3DS to replicate the DS's success (a likely insurmountable task even ignoring other factors), and the utter failure of the Vita have caused a big reduction in the overall size of the hardware market from its peak in 2008 (the PS4 & XBO are so far performing quite well in combined sales compared to their predecessors, as shown in my usual charts in these threads). A combination of the shrinkage of the handheld market, Nintendo's troubles with the Wii U, and the general dynamics of the console cycle could be a major contributing factor in the decline of software sales.

Of course, there's also fewer publishers and fewer games, but there's still some ambiguities. How many of those publishers were drawn in by the seventh-gen bubble and left when that bubble popped, how many were those were simply unable to deal with the financial realities of modern AAA development, and how many of those were simply gobbled up by other companies? As for the number of games published, how many of those were themselves a symptom of the hardware sales glut (esp. for handhelds) and how many were due to the higher number of publishers (a smaller amount of big companies could in principle publish as many titles as a bunch of smaller developers)? Handhelds especially were mostly exclusives, and the DS and PSP brought in a ton of unique titles, plus the lower costs of development meant extant publishers could theoretically release more titles for their buck than they could for home systems, especially for the 360 & PS3.

Unfortunately, without a more detailed breakdown going back further than 2009 (preferably back to 2000, if not earlier) as well as the software sales & number of titles split between handhelds and consoles, it'll be hard to clarify all the causal factors at work here.

Yes. While current-gen systems were up YoY, continuing rapid decline in last-gen console sales effectively negated it:

graph

But did PS4 win NPD? If yes, I can't see how you can disagree with him?

But it is not about winning or not, just create a thread 'who will win May's NPD?' and I can promised you the majority probably end up right.  My point is =>  Amazon April showed (one of) the biggest gaps between PS4 and Xbox one in sales ranking => NPD shows (one of) the smallest gaps ever.    100% maybe accurate on the one who won but people who would write a sales analysis based on the Amazon sales rankings are 100% wasting their time and I am fine if people do so in the amazon thread but it is annoying when someone use the sales ranking outside the amazon thread. I think it was Leo-J was posted that it will be a close one this month between xone and PS4 and compared to the amazon Sales ranking he is a prophet;