Some people have been saying that Sept-Dec console sales comes out to be roughly double Jan-Aug sales for the same year. Meaning predictions are going around saying PS4 will be at 20 million by the end of the year. This 1:2 ratio may well be true for most years, or as an average, but when you look at the first full year of a console's life cycle the ratio seems to be closer to 1:1.

Wii's first full year it was roughly 1:1

360's first full year is was a bit over 1:1

PS3's first full year was about 1:1

Wii U's was 1:1.67 but that came with a price cut, but is still well short of 1:2

So as it seems like PS4 is heading for about 5.5 million for the year to 1 Sept, it means we're looking at around 6 million for Sept to Dec (give or take half a million). And as PS4 LTD is going to be at roughly 10.3-10.5 million for the LTD to 1 Sept, that means 16.3-16.5 million LTD.

I think 16 million LTD is a very safe bet, and 17 million is quite possible. But I think it will be stretching it to go much beyond 17 million LTD by 1 Jan 2015.

The picture of course is not rosy for Xb one if the 1:1 ratio for first full year holds true. For Xb one we're looking at around 2.3 million by 1 Sept, so we are looking at possibly no more than 3 million for the rest of the year. To give Xb one a grand total of around 8 million by 1 January 2015.

Wii U being in its second full year should get closer to the 1:2 level, which means it should also do about 3 million from 1 Sept to 1 Jan. And that will put it at 10 million LTD by 1 Jan.

The average ratio is double but it may be as low as 83% as recorded in histroy due to several reasons. Also it is accurate to look at one single only but rather the entire generation due to the switch from userbase and the change in the market share and then adjust accordingly.

Also the PS3's first year performance sounds a nitpicked as it was prohibitively expensive and in short supply due to bluray and complex hardware issues. The consumer behavior is more general and different from that. Why don't you look at the collective behavior of the entire 7th generation?

After all, it would be very naive to suggest PS4 will not sell more in the second half of 2014 than the first one. The calculations have already been done with a good deal of confidence. At the end of the day your 16 million estimate is within the given range, but now that the VGChartz data is upped a bit, the figures may use a bit uphold.

2014 End Sales Estimates, more convincing than ever

Quote

"....In short, although the ranges somewhat move in either direction, the core estimates don't change

PS4
Original estimate : 13.7 - 17 mil
Half2 / Half1 estimate : 15.7 - 18 mil
Halves analysis update :  3.4 / 3.49 * (15.7 - 18 mil) = 15.3 - 17.5 mil

XB1
Original estimate : 6.3 - 9.8 mil
Half2 / Half1 estimate : 8.1 - 9.5 mil
Halves analysis update : 3.58 / 3.49 * (8.1 - 9.5 mil) = 8.3 - 9.7 mil

So we can now confidently say, by the end of 2014

PS4 will sell around 16-17 million
XB1 will sell around 8-9 million

...."

i think 16 million is impossible.

ps4 sales in japan not are good, there aren´t japanase games that helps to sell consoles there.

if ps4 had japanase important games, now ps4 could have about 12 million systems sold worldwide.

i think it could be possible sell to the end of the year about 12-14 million.

You seem to be disagreeing with me but then you come up with the same 16-17 million range. I'm not comparing 1H and 2H I am comparing 8 months to 4 months.

I do look at the collective behaviour of the entire 7th gen because I show Wii, 360 and PS3 year 1 ratios. If all 3 ratios individually are approximately 1:1 then the ratios combined will also be about 1:1. The first full year on the market looks like it reliably has the lowest 8mo:4mo ratio because of consistent factors: price is still usually the same as launch price, game library is still very cross generational, number of games that are only on new gen consoles is relatively small, and you may have supply limitations too. All these consistent multi generation factors are at play for PS4. Wii U had cut the price in it's first full year and its ratio did not quite reach 1:1.7.  Wii U probably also had more Wii U only games on it than PS4 or Xb one will have going in to this holiday, though I haven't analysed that assumption, so I may be wrong.

september, october, november, december.

4 months.

1 month = 4 weeks

4 month x 4 weeks = 16 weeks

if ps4 sells worldwide about 120,000 consoles per week...

120,000 per week x 16 weeks = 1.920,000 consoles worldwide to the end of the year 2014.

10,1 million consoles + 1,920,000 = 12,020,000 total consoles in 1 year and 2 months in the market.

as i said, is very difficult to sell 14 million or more but not impossible.

Hmmm...so it will sell just under 2 million between now and the end of the year? Hope you aren't planning to take bets on this, as it will be proven wrong by the beginning of Oct (at the lastest). And the holiday won't belong to the WiiU, if that's what you're getting at. I imagine it being outsold by both the X1 as well,  during the holiday.

OT: 16 million is doable, but I'm thinking a bit higher - 18 million.

Maybe 13 million, but definitely not 16.  If it's the Wii U or the New 3DS, it's still Nintendo's.